feat: add plot/vega/transform/sample/ctor

lib/node_modules/@stdlib/plot/vega/transform/sample/ctor/examples/index.js

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+/**
+* @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 SampleTransform = require( './../lib' );
+
+var transform = new SampleTransform({
+	'size': 500
+});
+
+console.log( transform.toJSON() );

lib/node_modules/@stdlib/plot/vega/transform/sample/ctor/lib/change_event.js

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+/**
+* @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;

lib/node_modules/@stdlib/plot/vega/transform/sample/ctor/lib/defaults.js

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+/**
+* @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 defaults.
+*
+* @private
+* @returns {Object} default options
+*
+* @example
+* var o = defaults();
+* // returns {...}
+*/
+function defaults() {
+	return {
+		// The maximum number of data objects to include in the sample:
+		'size': 1000
+	};
+}
+
+
+// EXPORTS //
+
+module.exports = defaults;

lib/node_modules/@stdlib/plot/vega/transform/sample/ctor/lib/index.js

@@ -0,0 +1,42 @@
+/**
+* @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';
+
+/**
+* Sample transform constructor.
+*
+* @module @stdlib/plot/vega/transform/sample/ctor
+*
+* @example
+* var SampleTransform = require( '@stdlib/plot/vega/transform/sample/ctor' );
+*
+* var transform = new SampleTransform({
+*     'size': 500
+* });
+* // returns <SampleTransform>
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;

lib/node_modules/@stdlib/plot/vega/transform/sample/ctor/lib/main.js

@@ -0,0 +1,199 @@
+/**
+* @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 getProperties = require( './properties/get.js' );
+
+var getSize = require( './size/get.js' );
+var setSize = require( './size/set.js' );
+
+
+// VARIABLES //
+
+var debug = logger( 'vega:sample-transform:main' );
+
+
+// MAIN //
+
+/**
+* Sample transform constructor.
+*
+* @constructor
+* @param {Options} options - constructor options
+* @param {NonNegativeNumber} [options.size=1000] - maximum number of data objects to include in the sample
+* @throws {TypeError} options argument must be an object
+* @throws {Error} must provide valid options
+* @returns {SampleTransform} sample transform instance
+*
+* @example
+* var transform = new SampleTransform({
+*     'size': 500
+* });
+* // returns <SampleTransform>
+*/
+function SampleTransform( options ) {
+	var opts;
+	var keys;
+	var v;
+	var k;
+	var i;
+	if ( !( this instanceof SampleTransform ) ) {
+		if ( arguments.length ) {
+			return new SampleTransform( options );
+		}
+		return new SampleTransform();
+	}
+	EventEmitter.call( this );
+
+	// 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 ];
+	}
+
+	// If no options were provided, return early with defaults...
+	if ( arguments.length === 0 ) {
+		return this;
+	}
+	if ( !isObject( options ) ) {
+		throw new TypeError( format( 'invalid argument. Options argument must be an object. Value: `%s`.', options ) );
+	}
+
+	// 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;
+}
+
+/*
+* Inherit from the `EventEmitter` prototype.
+*/
+inherit( SampleTransform, EventEmitter );
+
+/**
+* Constructor name.
+*
+* @private
+* @name name
+* @memberof SampleTransform
+* @readonly
+* @type {string}
+*/
+setNonEnumerableReadOnly( SampleTransform, 'name', 'SampleTransform' );
+
+/**
+* Maximum number of data objects to include in the sample.
+*
+* @name size
+* @memberof SampleTransform.prototype
+* @type {NonNegativeNumber}
+* @default 1000
+*
+* @example
+* var transform = new SampleTransform({
+*     'size': 500
+* });
+*
+* var v = transform.size;
+* // returns 500
+*/
+setReadWriteAccessor( SampleTransform.prototype, 'size', getSize, setSize );
+
+/**
+* Sample transform properties.
+*
+* @name properties
+* @memberof SampleTransform.prototype
+* @type {Array<string>}
+*
+* @example
+* var transform = new SampleTransform({
+*     'size': 500
+* });
+*
+* var v = transform.properties;
+* // returns [...]
+*/
+setNonEnumerableReadOnlyAccessor( SampleTransform.prototype, 'properties', getProperties );
+
+/**
+* Serializes an instance to a JSON object.
+*
+* ## Notes
+*
+* -   This method is implicitly invoked by `JSON.stringify`.
+*
+* @name toJSON
+* @memberof SampleTransform.prototype
+* @type {Function}
+* @returns {Object} JSON object
+*
+* @example
+* var transform = new SampleTransform({
+*     'size': 500
+* });
+*
+* var v = transform.toJSON();
+* // returns {...}
+*/
+setNonEnumerableReadOnly( SampleTransform.prototype, 'toJSON', function toJSON() {
+	return instance2json( this, properties );
+});
+
+
+// EXPORTS //
+
+module.exports = SampleTransform;

lib/node_modules/@stdlib/plot/vega/transform/sample/ctor/lib/properties.json

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+[
+  "size"
+]