diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/examples/index.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/examples/index.js
new file mode 100644
index 000000000000..1d971a98d70e
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/examples/index.js
@@ -0,0 +1,32 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+var Field = require( '@stdlib/plot/vega/field/ctor' );
+var PieTransform = require( './../lib' );
+
+var field = new Field({
+	'field': 'amount'
+});
+
+var transform = new PieTransform({
+	'field': field
+});
+
+console.log( transform.toJSON() );
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/get.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/get.js
new file mode 100644
index 000000000000..0954cb7b980b
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/get.js
@@ -0,0 +1,44 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var copy = require( '@stdlib/array/base/copy-indexed' );
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the output field names for the computed start and end angle values.
+*
+* @private
+* @returns {ArrayLikeObject<string>} field names
+*/
+function get() {
+	return copy( this[ prop.private ] );
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/properties.js
new file mode 100644
index 000000000000..3f2304dc2f08
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'as' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/set.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/set.js
new file mode 100644
index 000000000000..ecb96109c5e7
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/as/set.js
@@ -0,0 +1,63 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isStringArray = require( '@stdlib/assert/is-string-array' ).primitives;
+var hasEqualValues = require( '@stdlib/array/base/assert/has-equal-values' );
+var copy = require( '@stdlib/array/base/copy' );
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:pie-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the output field names for the computed start and end angle values.
+*
+* @private
+* @param {StringArray} value - input value
+* @throws {TypeError} must be an array of strings
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isStringArray( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be an array of strings. Value: `%s`.', prop.name, value ) );
+	}
+	if ( !hasEqualValues( value, this[ prop.private ] ) ) {
+		debug( 'Current value: %s. New value: %s.', JSON.stringify( this[ prop.private ] ), JSON.stringify( value ) );
+		this[ prop.private ] = copy( value );
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/change_event.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/change_event.js
new file mode 100644
index 000000000000..e444f9c667b0
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/change_event.js
@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MAIN //
+
+/**
+* Returns a new change event object.
+*
+* @private
+* @param {string} property - property name
+* @returns {Object} event object
+*/
+function event( property ) { // eslint-disable-line stdlib/no-redeclare
+	return {
+		'type': 'update',
+		'source': 'transform',
+		'property': property
+	};
+}
+
+
+// EXPORTS //
+
+module.exports = event;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/defaults.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/defaults.js
new file mode 100644
index 000000000000..284e73ce6b9f
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/defaults.js
@@ -0,0 +1,57 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var TWO_PI = require( '@stdlib/constants/float64/two-pi' );
+
+
+// MAIN //
+
+/**
+* Returns defaults.
+*
+* @private
+* @returns {Object} default options
+*
+* @example
+* var o = defaults();
+* // returns {...}
+*/
+function defaults() {
+	return {
+		// Output field names for the computed start and end angle values:
+		'as': [ 'startAngle', 'endAngle' ],
+
+		// End angle of the pie in radians:
+		'endAngle': TWO_PI,
+
+		// Boolean indicating whether to sort arcs according to field values:
+		'sort': false,
+
+		// Starting angle of the pie in radians:
+		'startAngle': 0.0
+	};
+}
+
+
+// EXPORTS //
+
+module.exports = defaults;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/get.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/get.js
new file mode 100644
index 000000000000..fc5a5e90fdd8
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the end angle of the pie in radians.
+*
+* @private
+* @returns {NonNegativeNumber} end angle
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/properties.js
new file mode 100644
index 000000000000..6cfbc9174fb6
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'endAngle' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/set.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/set.js
new file mode 100644
index 000000000000..34a694fe8636
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/end-angle/set.js
@@ -0,0 +1,61 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isNonNegativeNumber = require( '@stdlib/assert/is-nonnegative-number' ).isPrimitive;
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:pie-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the end angle of the pie in radians.
+*
+* @private
+* @param {NonNegativeNumber} value - input value
+* @throws {TypeError} must be a nonnegative number
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isNonNegativeNumber( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a nonnegative number. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', this[ prop.private ], value );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/get.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/get.js
new file mode 100644
index 000000000000..fe34b7dd00ef
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the data field determining pie slice size.
+*
+* @private
+* @returns {(Field|void)} data field
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/properties.js
new file mode 100644
index 000000000000..639ddb612903
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'field' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/set.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/set.js
new file mode 100644
index 000000000000..396505daaad7
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/field/set.js
@@ -0,0 +1,68 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isField = require( '@stdlib/plot/vega/base/assert/is-field' );
+var isUndefined = require( '@stdlib/assert/is-undefined' );
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:pie-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the data field determining pie slice size.
+*
+* ## Notes
+*
+* -   Providing `undefined` "unsets" the configured value, in which case all pie slices have an equal size.
+*
+* @private
+* @param {(Field|void)} value - input value
+* @throws {TypeError} must be a field instance
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isField( value ) && !isUndefined( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a field instance. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		this._removeChangeListener( this[ prop.private ] );
+		debug( 'Current value: %s. New value: %s.', JSON.stringify( this[ prop.private ] ), JSON.stringify( value ) );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+		this._addChangeListener( this[ prop.private ] );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/index.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/index.js
new file mode 100644
index 000000000000..85fc5a962e8f
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/index.js
@@ -0,0 +1,48 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+/**
+* Pie transform constructor.
+*
+* @module @stdlib/plot/vega/transform/pie/ctor
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+* var PieTransform = require( '@stdlib/plot/vega/transform/pie/ctor' );
+*
+* var field = new Field({
+*     'field': 'amount'
+* });
+* // returns <Field>
+*
+* var transform = new PieTransform({
+*     'field': field
+* });
+* // returns <PieTransform>
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/main.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/main.js
new file mode 100644
index 000000000000..8f1c97d0a36c
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/main.js
@@ -0,0 +1,383 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-restricted-syntax, no-invalid-this, stdlib/no-empty-lines-between-requires */
+
+'use strict';
+
+// MODULES //
+
+var EventEmitter = require( 'events' ).EventEmitter;
+var logger = require( 'debug' );
+var isObject = require( '@stdlib/assert/is-object' );
+var setNonEnumerableReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' );
+var setNonEnumerableReadOnlyAccessor = require( '@stdlib/utils/define-nonenumerable-read-only-accessor' ); // eslint-disable-line id-length
+var setReadWriteAccessor = require( '@stdlib/utils/define-read-write-accessor' );
+var hasProp = require( '@stdlib/assert/has-property' );
+var inherit = require( '@stdlib/utils/inherit' );
+var objectKeys = require( '@stdlib/utils/keys' );
+var instance2json = require( '@stdlib/plot/vega/base/to-json' );
+var transformErrorMessage = require( '@stdlib/plot/vega/base/transform-validation-message' );
+var format = require( '@stdlib/string/format' );
+var properties = require( './properties.json' );
+var defaults = require( './defaults.js' );
+
+// Note: keep the following in alphabetical order according to the `require` path...
+var getAs = require( './as/get.js' );
+var setAs = require( './as/set.js' );
+
+var getEndAngle = require( './end-angle/get.js' );
+var setEndAngle = require( './end-angle/set.js' );
+
+var getField = require( './field/get.js' );
+var setField = require( './field/set.js' );
+
+var getProperties = require( './properties/get.js' );
+
+var getSort = require( './sort/get.js' );
+var setSort = require( './sort/set.js' );
+
+var getStartAngle = require( './start-angle/get.js' );
+var setStartAngle = require( './start-angle/set.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:pie-transform:main' );
+
+
+// MAIN //
+
+/**
+* Pie transform constructor.
+*
+* @constructor
+* @param {Options} options - constructor options
+* @param {ArrayLikeObject<string>} [options.as=['startAngle','endAngle']] - output field names for the computed start and end angle values
+* @param {NonNegativeNumber} [options.endAngle=2*PI] - end angle of the pie in radians
+* @param {Field} [options.field] - data field determining pie slice size (if not provided, all pie slices have an equal size)
+* @param {boolean} [options.sort=false] - boolean indicating whether to sort arcs according to field values
+* @param {NonNegativeNumber} [options.startAngle=0] - starting angle of the pie in radians
+* @throws {TypeError} options argument must be an object
+* @throws {Error} must provide valid options
+* @returns {PieTransform} pie transform instance
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var field = new Field({
+*     'field': 'amount'
+* });
+* // returns <Field>
+*
+* var transform = new PieTransform({
+*     'field': field
+* });
+* // returns <PieTransform>
+*/
+function PieTransform( options ) {
+	var self;
+	var opts;
+	var keys;
+	var v;
+	var k;
+	var i;
+	if ( !( this instanceof PieTransform ) ) {
+		return new PieTransform( options );
+	}
+	self = this;
+	EventEmitter.call( this );
+
+	if ( !isObject( options ) ) {
+		throw new TypeError( format( 'invalid argument. Options argument must be an object. Value: `%s`.', options ) );
+	}
+
+	// Resolve the default configuration:
+	opts = defaults();
+
+	// Set internal properties according to the default configuration...
+	keys = objectKeys( opts );
+	for ( i = 0; i < keys.length; i++ ) {
+		k = keys[ i ];
+		this[ '_'+k ] = opts[ k ];
+	}
+
+	// Define an internal change event listener:
+	this._onChange = onChange;
+
+	// Add change listeners to default event emitters:
+	if ( this._field && typeof this._field.on === 'function' ) {
+		this._addChangeListener( this._field );
+	}
+
+	// Validate provided options by attempting to assign option values to corresponding fields...
+	for ( i = 0; i < properties.length; i++ ) {
+		k = properties[ i ];
+		if ( !hasProp( options, k ) ) {
+			continue;
+		}
+		v = options[ k ];
+		try {
+			this[ k ] = v;
+		} catch ( err ) {
+			debug( 'Encountered an error. Error: %s', err.message );
+
+			// FIXME: retain thrown error type
+			throw new Error( transformErrorMessage( err.message ) );
+		}
+	}
+	return this;
+
+	/**
+	* Callback invoked upon a change event.
+	*
+	* @private
+	* @param {Object} event - event object
+	*/
+	function onChange( event ) {
+		debug( 'Received a change event: %s', JSON.stringify( event ) );
+		self.emit( 'change', event );
+	}
+}
+
+/*
+* Inherit from the `EventEmitter` prototype.
+*/
+inherit( PieTransform, EventEmitter );
+
+/**
+* Constructor name.
+*
+* @private
+* @name name
+* @memberof PieTransform
+* @readonly
+* @type {string}
+*/
+setNonEnumerableReadOnly( PieTransform, 'name', 'PieTransform' );
+
+/**
+* Adds an internal listener to a change event on a child instance.
+*
+* @private
+* @name _addChangeListener
+* @memberof PieTransform.prototype
+* @type {Function}
+* @param {Object} emitter - event emitter
+* @returns {PieTransform} pie transform instance
+*/
+setNonEnumerableReadOnly( PieTransform.prototype, '_addChangeListener', function addChangeListener( emitter ) {
+	if ( emitter && typeof emitter.on === 'function' ) {
+		emitter.on( 'change', this._onChange );
+	}
+	return this;
+});
+
+/**
+* Adds internal listeners to change events on child instances.
+*
+* @private
+* @name _addChangeListeners
+* @memberof PieTransform.prototype
+* @type {Function}
+* @param {ArrayLikeObject<Object>} emitters - list of event emitters
+* @returns {PieTransform} pie transform instance
+*/
+setNonEnumerableReadOnly( PieTransform.prototype, '_addChangeListeners', function addChangeListeners( emitters ) {
+	var i;
+	for ( i = 0; i < emitters.length; i++ ) {
+		this._addChangeListener( emitters[ i ] );
+	}
+	return this;
+});
+
+/**
+* Removes an internal listener to a change event on a child instance.
+*
+* @private
+* @name _removeChangeListener
+* @memberof PieTransform.prototype
+* @type {Function}
+* @param {Object} emitter - event emitter
+* @returns {PieTransform} pie transform instance
+*/
+setNonEnumerableReadOnly( PieTransform.prototype, '_removeChangeListener', function removeChangeListener( emitter ) {
+	if ( emitter && typeof emitter.removeListener === 'function' ) {
+		emitter.removeListener( 'change', this._onChange );
+	}
+	return this;
+});
+
+/**
+* Removes internal listeners to change events on child instances.
+*
+* @private
+* @name _removeChangeListeners
+* @memberof PieTransform.prototype
+* @type {Function}
+* @param {ArrayLikeObject<Object>} emitters - list of event emitters
+* @returns {PieTransform} pie transform instance
+*/
+setNonEnumerableReadOnly( PieTransform.prototype, '_removeChangeListeners', function removeChangeListeners( emitters ) {
+	var i;
+	for ( i = 0; i < emitters.length; i++ ) {
+		this._removeChangeListener( emitters[ i ] );
+	}
+	return this;
+});
+
+/**
+* Output field names for the computed start and end angle values.
+*
+* @name as
+* @memberof PieTransform.prototype
+* @type {ArrayLikeObject<string>}
+* @default ['startAngle','endAngle']
+*
+* @example
+* var transform = new PieTransform({
+*     'as': [ 'foo', 'bar' ]
+* });
+*
+* var v = transform.as;
+* // returns [ 'foo', 'bar' ]
+*/
+setReadWriteAccessor( PieTransform.prototype, 'as', getAs, setAs );
+
+/**
+* End angle of the pie in radians.
+*
+* @name endAngle
+* @memberof PieTransform.prototype
+* @type {NonNegativeNumber}
+* @default 2*PI
+*
+* @example
+* var transform = new PieTransform({
+*     'endAngle': 3.141592653589793
+* });
+*
+* var v = transform.endAngle;
+* // returns 3.141592653589793
+*/
+setReadWriteAccessor( PieTransform.prototype, 'endAngle', getEndAngle, setEndAngle );
+
+/**
+* Data field determining pie slice size.
+*
+* ## Notes
+*
+* -   If not set, all pie slices have an equal size.
+*
+* @name field
+* @memberof PieTransform.prototype
+* @type {(Field|void)}
+*
+* @example
+* var Field = require( '@stdlib/plot/vega/field/ctor' );
+*
+* var field = new Field({
+*     'field': 'amount'
+* });
+*
+* var transform = new PieTransform({
+*     'field': field
+* });
+*
+* var v = transform.field;
+* // returns <Field>
+*/
+setReadWriteAccessor( PieTransform.prototype, 'field', getField, setField );
+
+/**
+* Pie transform properties.
+*
+* @name properties
+* @memberof PieTransform.prototype
+* @type {Array<string>}
+*
+* @example
+* var transform = new PieTransform({});
+*
+* var v = transform.properties;
+* // returns [...]
+*/
+setNonEnumerableReadOnlyAccessor( PieTransform.prototype, 'properties', getProperties );
+
+/**
+* Boolean indicating whether to sort arcs according to field values.
+*
+* @name sort
+* @memberof PieTransform.prototype
+* @type {boolean}
+* @default false
+*
+* @example
+* var transform = new PieTransform({
+*     'sort': true
+* });
+*
+* var v = transform.sort;
+* // returns true
+*/
+setReadWriteAccessor( PieTransform.prototype, 'sort', getSort, setSort );
+
+/**
+* Starting angle of the pie in radians.
+*
+* @name startAngle
+* @memberof PieTransform.prototype
+* @type {NonNegativeNumber}
+* @default 0
+*
+* @example
+* var transform = new PieTransform({
+*     'startAngle': 1.5707963267948966
+* });
+*
+* var v = transform.startAngle;
+* // returns 1.5707963267948966
+*/
+setReadWriteAccessor( PieTransform.prototype, 'startAngle', getStartAngle, setStartAngle );
+
+/**
+* Serializes an instance to a JSON object.
+*
+* ## Notes
+*
+* -   This method is implicitly invoked by `JSON.stringify`.
+*
+* @name toJSON
+* @memberof PieTransform.prototype
+* @type {Function}
+* @returns {Object} JSON object
+*
+* @example
+* var transform = new PieTransform({});
+*
+* var v = transform.toJSON();
+* // returns {...}
+*/
+setNonEnumerableReadOnly( PieTransform.prototype, 'toJSON', function toJSON() {
+	return instance2json( this, properties );
+});
+
+
+// EXPORTS //
+
+module.exports = PieTransform;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/properties.json b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/properties.json
new file mode 100644
index 000000000000..223aa8ec7bcc
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/properties.json
@@ -0,0 +1,7 @@
+[
+  "as",
+  "endAngle",
+  "field",
+  "sort",
+  "startAngle"
+]
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/properties/get.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/properties/get.js
new file mode 100644
index 000000000000..f3cbb28454ea
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/properties/get.js
@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var properties = require( './../properties.json' );
+
+
+// MAIN //
+
+/**
+* Returns the list of enumerable properties.
+*
+* @private
+* @returns {Array<string>} properties
+*/
+function get() {
+	return properties.slice();
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/get.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/get.js
new file mode 100644
index 000000000000..6ba462ba947a
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns a boolean indicating whether to sort arcs according to field values.
+*
+* @private
+* @returns {boolean} boolean indicating whether to sort arcs
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/properties.js
new file mode 100644
index 000000000000..9a3846787a90
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'sort' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/set.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/set.js
new file mode 100644
index 000000000000..9dab1e323e57
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/sort/set.js
@@ -0,0 +1,61 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isBoolean = require( '@stdlib/assert/is-boolean' ).isPrimitive;
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:pie-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets a boolean indicating whether to sort arcs according to field values.
+*
+* @private
+* @param {boolean} value - input value
+* @throws {TypeError} must be a boolean
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isBoolean( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a boolean. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', this[ prop.private ], value );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/get.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/get.js
new file mode 100644
index 000000000000..ece3d9c3f167
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/get.js
@@ -0,0 +1,43 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var prop = require( './properties.js' );
+
+
+// MAIN //
+
+/**
+* Returns the starting angle of the pie in radians.
+*
+* @private
+* @returns {NonNegativeNumber} starting angle
+*/
+function get() {
+	return this[ prop.private ];
+}
+
+
+// EXPORTS //
+
+module.exports = get;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/properties.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/properties.js
new file mode 100644
index 000000000000..7509ef0cbba7
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/properties.js
@@ -0,0 +1,33 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var property2object = require( '@stdlib/plot/vega/base/property2object' );
+
+
+// MAIN //
+
+var obj = property2object( 'startAngle' );
+
+
+// EXPORTS //
+
+module.exports = obj;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/set.js b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/set.js
new file mode 100644
index 000000000000..ad02ac451c6d
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/lib/start-angle/set.js
@@ -0,0 +1,61 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+/* eslint-disable no-invalid-this */
+
+'use strict';
+
+// MODULES //
+
+var logger = require( 'debug' );
+var isNonNegativeNumber = require( '@stdlib/assert/is-nonnegative-number' ).isPrimitive;
+var format = require( '@stdlib/string/format' );
+var changeEvent = require( './../change_event.js' );
+var prop = require( './properties.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:pie-transform:set:'+prop.name );
+
+
+// MAIN //
+
+/**
+* Sets the starting angle of the pie in radians.
+*
+* @private
+* @param {NonNegativeNumber} value - input value
+* @throws {TypeError} must be a nonnegative number
+* @returns {void}
+*/
+function set( value ) {
+	if ( !isNonNegativeNumber( value ) ) {
+		throw new TypeError( format( 'invalid assignment. `%s` must be a nonnegative number. Value: `%s`.', prop.name, value ) );
+	}
+	if ( value !== this[ prop.private ] ) {
+		debug( 'Current value: %s. New value: %s.', this[ prop.private ], value );
+		this[ prop.private ] = value;
+		this.emit( 'change', changeEvent( prop.name ) );
+	}
+}
+
+
+// EXPORTS //
+
+module.exports = set;
diff --git a/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/package.json b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/package.json
new file mode 100644
index 000000000000..f4cb6721d0f3
--- /dev/null
+++ b/lib/node_modules/@stdlib/plot/vega/transform/pie/ctor/package.json
@@ -0,0 +1,61 @@
+{
+  "name": "@stdlib/plot/vega/transform/pie/ctor",
+  "version": "0.0.0",
+  "description": "Pie transform constructor.",
+  "license": "Apache-2.0",
+  "author": {
+    "name": "The Stdlib Authors",
+    "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+  },
+  "contributors": [
+    {
+      "name": "The Stdlib Authors",
+      "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+    }
+  ],
+  "main": "./lib",
+  "directories": {
+    "benchmark": "./benchmark",
+    "doc": "./docs",
+    "example": "./examples",
+    "lib": "./lib",
+    "test": "./test"
+  },
+  "types": "./docs/types",
+  "scripts": {},
+  "homepage": "https://github.com/stdlib-js/stdlib",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/stdlib-js/stdlib.git"
+  },
+  "bugs": {
+    "url": "https://github.com/stdlib-js/stdlib/issues"
+  },
+  "dependencies": {},
+  "devDependencies": {},
+  "engines": {
+    "node": ">=0.10.0",
+    "npm": ">2.7.0"
+  },
+  "os": [
+    "aix",
+    "darwin",
+    "freebsd",
+    "linux",
+    "macos",
+    "openbsd",
+    "sunos",
+    "win32",
+    "windows"
+  ],
+  "keywords": [
+    "stdlib",
+    "plot",
+    "vega",
+    "transform",
+    "pie",
+    "constructor",
+    "ctor"
+  ],
+  "__stdlib__": {}
+}