feat: add keys method to array/complex64

PR-URL: #2160
Co-authored-by: Athan Reines <kgryte@gmail.com>
Reviewed-by: Athan Reines <kgryte@gmail.com>

Author: Jaysukh-409

lib/node_modules/@stdlib/array/complex64/README.md

@@ -1512,6 +1512,35 @@ var str = arr.join( '/' );
 // returns '1 + 1i/2 - 2i/3 + 3i'
 ```
 
+<a name="method-keys"></a>
+
+#### Complex64Array.prototype.keys()
+
+Returns an iterator for iterating over each index key in a typed array.
+
+```javascript
+var arr = new Complex64Array( 2 );
+
+arr.set( [ 1.0, -1.0 ], 0 );
+arr.set( [ 2.0, -2.0 ], 1 );
+
+var iter = arr.keys();
+
+var v = iter.next().value;
+// returns 0
+
+v = iter.next().value;
+// returns 1
+
+var bool = iter.next().done;
+// returns true
+```
+
+The returned [iterator][mdn-iterator-protocol] protocol-compliant object has the following properties:
+
+-   **next**: function which returns an [iterator][mdn-iterator-protocol] protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the [iterator][mdn-iterator-protocol] is finished.
+-   **return**: function which closes an [iterator][mdn-iterator-protocol] and returns a single (optional) argument in an [iterator][mdn-iterator-protocol] protocol-compliant object.
+
 <a name="method-last-index-of"></a>
 
 #### Complex64Array.prototype.lastIndexOf( searchElement\[, fromIndex] )

lib/node_modules/@stdlib/array/complex64/benchmark/benchmark.keys.js

@@ -0,0 +1,51 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 bench = require( '@stdlib/bench' );
+var isIteratorLike = require( '@stdlib/assert/is-iterator-like' );
+var pkg = require( './../package.json' ).name;
+var Complex64Array = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg+':keys:len=2', function benchmark( b ) {
+	var iter;
+	var arr;
+	var i;
+
+	arr = new Complex64Array( [ 1.0, -1.0, 2.0, -2.0 ] );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		iter = arr.keys();
+		if ( typeof iter !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isIteratorLike( iter ) ) {
+		b.fail( 'should return an iterator protocol-compliant object' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/array/complex64/benchmark/benchmark.keys.length.js

@@ -0,0 +1,103 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 bench = require( '@stdlib/bench' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var Complex64 = require( '@stdlib/complex/float32' );
+var isIteratorLike = require('@stdlib/assert/is-iterator-like');
+var pkg = require( './../package.json' ).name;
+var Complex64Array = require( './../lib' );
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var arr;
+	var i;
+
+	arr = [];
+	for ( i = 0; i < len; i++ ) {
+		arr.push( new Complex64( i, i ) );
+	}
+	arr = new Complex64Array( arr );
+
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var iter;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			iter = arr.keys();
+			if ( typeof iter !== 'object' ) {
+				b.fail( 'should return an object' );
+			}
+		}
+		b.toc();
+		if ( !isIteratorLike( iter ) ) {
+			b.fail( 'should return an iterator protocol-compliant object' );
+		}
+		b.pass( 'benchmark finished' );
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+	var len;
+	var min;
+	var max;
+	var f;
+	var i;
+
+	min = 1; // 10^min
+	max = 6; // 10^max
+
+	for ( i = min; i <= max; i++ ) {
+		len = pow( 10, i );
+		f = createBenchmark( len );
+		bench( pkg+':keys:len='+len, f );
+	}
+}
+
+main();

lib/node_modules/@stdlib/array/complex64/docs/types/index.d.ts

@@ -802,6 +802,30 @@ declare class Complex64Array implements Complex64ArrayInterface {
 	*/
 	join( separator?: string ): string;
 
+	/**
+	* Returns an iterator for iterating over each index key in a typed array.
+	*
+	* @returns iterator
+	*
+	* @example
+	* var arr = new Complex64Array( 2 );
+	*
+	* arr.set( [ 1.0, 1.0 ], 0 );
+	* arr.set( [ 2.0, 2.0 ], 1 );
+	*
+	* var iter = arr.keys();
+	*
+	* var v = iter.next().value;
+	* // returns 0
+	*
+	* v = iter.next().value;
+	* // returns 1
+	*
+	* var bool = iter.next().done;
+	* // returns true
+	*/
+	keys(): TypedIterator<number>;
+
 	/**
 	* Returns the last index at which a given element can be found.
 	*

lib/node_modules/@stdlib/array/complex64/lib/main.js

@@ -1535,6 +1535,107 @@ setReadOnly( Complex64Array.prototype, 'join', function join( separator ) {
 	return out.join( sep );
 });
 
+/**
+* Returns an iterator for iterating over each index key in a typed array.
+*
+* @name keys
+* @memberof Complex64Array.prototype
+* @type {Function}
+* @throws {TypeError} `this` must be a complex number array
+* @returns {Iterator} iterator
+*
+* @example
+* var arr = new Complex64Array( 2 );
+*
+* arr.set( [ 1.0, 1.0 ], 0 );
+* arr.set( [ 2.0, 2.0 ], 1 );
+*
+* var iter = arr.keys();
+*
+* var v = iter.next().value;
+* // returns 0
+*
+* v = iter.next().value;
+* // returns 1
+*
+* var bool = iter.next().done;
+* // returns true
+*/
+setReadOnly( Complex64Array.prototype, 'keys', function keys() {
+	var self;
+	var iter;
+	var len;
+	var FLG;
+	var i;
+	if ( !isComplexArray( this ) ) {
+		throw new TypeError( 'invalid invocation. `this` is not a complex number array.' );
+	}
+	self = this;
+	len = this._length;
+
+	// Initialize an iteration index:
+	i = -1;
+
+	// Create an iterator protocol-compliant object:
+	iter = {};
+	setReadOnly( iter, 'next', next );
+	setReadOnly( iter, 'return', end );
+
+	if ( ITERATOR_SYMBOL ) {
+		setReadOnly( iter, ITERATOR_SYMBOL, factory );
+	}
+	return iter;
+
+	/**
+	* Returns an iterator protocol-compliant object containing the next iterated value.
+	*
+	* @private
+	* @returns {Object} iterator protocol-compliant object
+	*/
+	function next() {
+		i += 1;
+		if ( FLG || i >= len ) {
+			return {
+				'done': true
+			};
+		}
+		return {
+			'value': i,
+			'done': false
+		};
+	}
+
+	/**
+	* Finishes an iterator.
+	*
+	* @private
+	* @param {*} [value] - value to return
+	* @returns {Object} iterator protocol-compliant object
+	*/
+	function end( value ) {
+		FLG = true;
+		if ( arguments.length ) {
+			return {
+				'value': value,
+				'done': true
+			};
+		}
+		return {
+			'done': true
+		};
+	}
+
+	/**
+	* Returns a new iterator.
+	*
+	* @private
+	* @returns {Iterator} iterator
+	*/
+	function factory() {
+		return self.keys();
+	}
+});
+
 /**
 * Returns the last index at which a given element can be found.
 *