feat: add findLastIndex method to arra/fixed-endian-factory

Author: aayush0325

lib/node_modules/@stdlib/array/fixed-endian-factory/README.md

@@ -451,6 +451,54 @@ var count = context.count;
 // returns 3
 ```
 
+<a name="method-find-last-index">
+
+#### TypedArray.prototype.findLastIndex( predicate\[, thisArg] )
+
+Returns the index of the last element in an array for which a predicate function returns a truthy value.
+
+```javascript
+function predicate( v ) {
+    return v % 2 !== 0;
+}
+
+var Float64ArrayFE = fixedEndianFactory( 'float64' );
+
+var arr = new Float64ArrayFE( 'little-endian', [ 1.0, 2.0, 3.0, 4.0, 2.0 ] );
+
+var out = arr.findLastIndex( predicate );
+// returns 2
+```
+
+The `predicate` function is provided three arguments:
+
+-   **value**: current array element.
+-   **index**: current array element index.
+-   **arr**: the array on which this method was called.
+
+To set the function execution context, provide a `thisArg`.
+
+```javascript
+function predicate( v ) {
+    this.count += 1;
+    return v % 2 !== 0;
+}
+
+var Float64ArrayFE = fixedEndianFactory( 'float64' );
+
+var arr = new Float64ArrayFE( 'little-endian', [ 1.0, 2.0, 3.0, 4.0, 2.0 ] );
+
+var context = {
+    'count': 0
+};
+
+var out = arr.findLastIndex( predicate, context );
+// returns 2
+
+var count = context.count;
+// returns 3
+```
+
 <a name="method-get"></a>
 
 #### TypedArrayFE.prototype.get( i )

lib/node_modules/@stdlib/array/fixed-endian-factory/benchmark/benchmark.find_last_index.js

@@ -0,0 +1,60 @@
+/**
+* @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 isInteger = require( '@stdlib/assert/is-integer' ).isPrimitive;
+var pkg = require( './../package.json' ).name;
+var factory = require( './../lib' );
+
+
+// VARIABLES //
+
+var Float64ArrayFE = factory( 'float64' );
+
+
+// MAIN //
+
+bench( pkg+':findLastIndex', function benchmark( b ) {
+	var arr;
+	var out;
+	var i;
+
+	arr = new Float64ArrayFE( 'little-endian', [ 1.0, 2.0, 2.0, 4.0 ] );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = arr.findLastIndex( predicate );
+		if ( typeof out !== 'number' ) {
+			b.fail( 'should return a number' );
+		}
+	}
+	b.toc();
+	if ( !isInteger( out ) ) {
+		b.fail( 'should return an integer' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+
+	function predicate( v ) {
+		return v % 2 !== 0;
+	}
+});

lib/node_modules/@stdlib/array/fixed-endian-factory/benchmark/benchmark.find_last_index.length.js

@@ -0,0 +1,113 @@
+/**
+* @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 zeroTo = require( '@stdlib/array/zero-to' );
+var isInteger = require( '@stdlib/assert/is-integer' ).isPrimitive;
+var pkg = require( './../package.json' ).name;
+var factory = require( './../lib' );
+
+
+// VARIABLES //
+
+var Float64ArrayFE = factory( 'float64' );
+
+
+// FUNCTIONS //
+
+/**
+* Predicate function.
+*
+* @private
+* @param {number} value - array element
+* @param {NonNegativeInteger} idx - array element index
+* @param {TypedArray} arr - array instance
+* @returns {boolean} boolean indicating whether a value passes a test
+*/
+function predicate( value ) {
+	return value % 2 === 0;
+}
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var arr = new Float64ArrayFE( 'little-endian', zeroTo( len ) );
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var out;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			out = arr.findLastIndex( predicate );
+			if ( typeof out !== 'number' ) {
+				b.fail( 'should return a number' );
+			}
+		}
+		b.toc();
+		if ( !isInteger( out ) ) {
+			b.fail( 'should return an integer' );
+		}
+		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+':findLastIndex:len='+len, f );
+	}
+}
+
+main();

lib/node_modules/@stdlib/array/fixed-endian-factory/lib/main.js

@@ -609,6 +609,38 @@ function factory( dtype ) { // eslint-disable-line max-lines-per-function, stdli
 		}
 	});
 
+	/**
+	* Returns the index of the last element in an array for which a predicate function returns a truthy value.
+	*
+	* @name findLastIndex
+	* @memberof TypedArray.prototype
+	* @type {Function}
+	* @param {Function} predicate - predicate function
+	* @param {*} [thisArg] - predicate function execution context
+	* @throws {TypeError} `this` must be a typed array
+	* @throws {TypeError} first argument must be a function
+	* @returns {integer} index or -1
+	*/
+	setReadOnly( TypedArray.prototype, 'findLastIndex', function findLastIndex( predicate, thisArg ) {
+		var buf;
+		var len;
+		var i;
+		if ( !isTypedArray( this ) ) {
+			throw new TypeError( format( 'invalid invocation. `this` is not %s %s.', CHAR2ARTICLE[ dtype[0] ], CTOR_NAME ) );
+		}
+		if ( !isFunction( predicate ) ) {
+			throw new TypeError( format( 'invalid argument. First argument must be a function. Value: `%s`.', predicate ) );
+		}
+		buf = this._buffer;
+		len = this._length;
+		for ( i = len - 1; i >= 0; i-- ) {
+			if ( predicate.call( thisArg, buf[ GETTER ]( i * BYTES_PER_ELEMENT, this._isLE ), i, this ) ) {
+				return i;
+			}
+		}
+		return -1;
+	});
+
 	/**
 	* Returns an array element.
 	*