feat: add at method to array/uint64

lib/node_modules/@stdlib/array/uint64/README.md

@@ -211,7 +211,7 @@ var arr = Uint64Array.from( [ 1, 2 ], mapFcn );
 A callback function is provided two arguments:
 
 -   **value**: source value.
--   **index**: source index..
+-   **index**: source index.
 
 To set the callback execution context, provide a `thisArg`.
 
@@ -243,6 +243,41 @@ var arr = Uint64Array.of( 1, 2 );
 // returns <Uint64Array>[ 1n, 2n ]
 ```
 
+<a name="method-at"></a>
+
+#### Uint64Array.prototype.at( i )
+
+Returns an array element located at integer position (index) `i`, with support for both nonnegative and negative integer positions.
+
+```javascript
+var arr = new Uint64Array( 10 );
+
+// Set the first, second, and last elements:
+arr.set( 1, 0 );
+arr.set( 2, 1 );
+arr.set( 9, 9 );
+
+// Get the first element:
+var z = arr.at( 0 );
+// returns <Uint64>[ 1n ]
+
+// Get the last element:
+z = arr.at( -1 );
+// returns <Uint64>[ 9n ]
+```
+
+If provided an out-of-bounds index, the method returns `undefined`.
+
+```javascript
+var arr = new Uint64Array( 10 );
+
+var z = arr.at( 100 );
+// returns undefined
+
+z = arr.at( -100 );
+// returns undefined
+```
+
 <a name="method-get"></a>
 
 #### Uint64Array.prototype.get( i )
@@ -391,7 +426,7 @@ var arr = [
 out = new Uint64Array( arr );
 logEach( '%s', out );
 
-// Create a 64-bit unsigned integer array from an typed array:
+// Create a 64-bit unsigned integer array from a typed array:
 arr = new Uint32Array( [ 1, 2, 3, 4 ] );
 out = new Uint64Array( arr );
 logEach( '%s', out );

lib/node_modules/@stdlib/array/uint64/benchmark/benchmark.at.js

@@ -0,0 +1,87 @@
+/**
+* @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 bench = require( '@stdlib/bench' );
+var format = require( '@stdlib/string/format' );
+var isUint64 = require( '@stdlib/assert/is-uint64' );
+var Uint64 = require( '@stdlib/number/uint64/ctor' );
+var pkg = require( './../package.json' ).name;
+var Uint64Array = require( './../lib' );
+
+
+// MAIN //
+
+bench( format( '%s::nonnegative_indices:at', pkg ), function benchmark( b ) {
+	var arr;
+	var N;
+	var u;
+	var i;
+
+	arr = [];
+	for ( i = 0; i < 10; i++ ) {
+		arr.push( new Uint64( i ) );
+	}
+	arr = new Uint64Array( arr );
+	N = arr.length;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		u = arr.at( i%N );
+		if ( typeof u !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isUint64( u ) ) {
+		b.fail( 'should return a 64-bit unsigned integer' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( format( '%s::negative_indices:at', pkg ), function benchmark( b ) {
+	var arr;
+	var N;
+	var u;
+	var i;
+
+	arr = [];
+	for ( i = 0; i < 10; i++ ) {
+		arr.push( new Uint64( i ) );
+	}
+	arr = new Uint64Array( arr );
+	N = arr.length;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		u = arr.at( -(i%N)-1 );
+		if ( typeof u !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isUint64( u ) ) {
+		b.fail( 'should return a 64-bit unsigned integer' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/array/uint64/docs/repl.txt

@@ -227,6 +227,31 @@
     5
 
 
+{{alias}}.prototype.at( i )
+    Returns an array element located at integer position (index) `i`, with
+    support for both nonnegative and negative integer positions.
+
+    If provided an index outside the array index range, the method returns
+    `undefined`.
+
+    Parameters
+    ----------
+    i: integer
+        Element index.
+
+    Returns
+    -------
+    out: Uint64|void
+        Array element or `undefined`.
+
+    Examples
+    --------
+    > var arr = new {{alias}}( [ 1, 2 ] )
+    <Uint64Array>[ 1n, 2n ]
+    > var z = arr.at( 1 )
+    <Uint64>[ 2n ]
+
+
 {{alias}}.prototype.get( i )
     Returns an array element located at integer position (index) `i`.
 

lib/node_modules/@stdlib/array/uint64/docs/types/index.d.ts

@@ -399,6 +399,33 @@ declare class Uint64Array implements Uint64ArrayInterface {
 	*/
 	readonly length: number;
 
+	/**
+	* Returns an array element located at integer position (index) `i`, with support for both nonnegative and negative integer indices.
+	*
+	* @param i - element index
+	* @throws index argument must be an integer
+	* @returns array element
+	*
+	* @example
+	* var arr = new Uint64Array( 10 );
+	*
+	* var u = arr.at( 0 );
+	* // returns <Uint64>[ 0n ]
+	*
+	* arr.set( 1, 0 );
+	* arr.set( 9, 9 );
+	*
+	* u = arr.at( -1 );
+	* // returns <Uint64>[ 9n ]
+	*
+	* u = arr.at( 100 );
+	* // returns undefined
+	*
+	* u = arr.at( -100 );
+	* // returns undefined
+	*/
+	at( i: number ): Uint64 | void;
+
 	/**
 	* Returns an array element.
 	*

lib/node_modules/@stdlib/array/uint64/examples/index.js

@@ -36,7 +36,7 @@ var arr = [
 out = new Uint64Array( arr );
 logEach( '%s', out );
 
-// Create a 64-bit unsigned integer array from an typed array:
+// Create a 64-bit unsigned integer array from a typed array:
 arr = new Uint32Array( [ 1, 2, 3, 4 ] );
 out = new Uint64Array( arr );
 logEach( '%s', out );

lib/node_modules/@stdlib/array/uint64/lib/main.js

@@ -477,6 +477,55 @@
 	return new this( args );
 });
 
+/**
+* Returns an array element located at integer position (index) `i`, with support for both nonnegative and negative integer indices.
+*
+* @name at
+* @memberof Uint64Array.prototype
+* @type {Function}
+* @param {integer} idx - element index
+* @throws {TypeError} `this` must be a 64-bit unsigned integer array
+* @throws {TypeError} must provide an integer
+* @returns {(Uint64|void)} array element
+*
+* @example
+* var arr = new Uint64Array( 10 );
+*
+* var u = arr.at( 0 );
+* // returns <Uint64>[ 0n ]
+*
+* arr.set( 1, 0 );
+* arr.set( 2, 1 );
+* arr.set( 9, 9 );
+*
+* u = arr.at( 0 );
+* // returns <Uint64>[ 1n ]
+*
+* u = arr.at( -1 );
+* // returns <Uint64>[ 9n ]
+*
+* u = arr.at( 100 );
+* // returns undefined
+*
+* u = arr.at( -100 );
+* // returns undefined
+*/
+setReadOnly( Uint64Array.prototype, 'at', function at( idx ) {
+	if ( !isUint64Array( this ) ) {
+		throw new TypeError( 'invalid invocation. `this` is not a 64-bit unsigned integer array.' );
+	}
+	if ( !isInteger( idx ) ) {
+		throw new TypeError( format( 'invalid argument. Must provide an integer. Value: `%s`.', idx ) );
+	}
+	if ( idx < 0 ) {
+		idx += this._length;
+	}
+	if ( idx < 0 || idx >= this._length ) {
+		return;
+	}
+	return getUint64( this._buffer, idx );
+});
+
 /**
 * Pointer to the underlying data buffer.
 *
@@ -685,7 +734,7 @@
 		buf[ idx+indices.LOW ] = words[ 1 ];
 		return;
 	}
 	if ( isNonNegativeInteger( value ) || ( isBigInt( value ) && isNonNegativeInteger( Number( value ) ) ) ) {
 		if ( idx >= this._length ) {
 			throw new RangeError( format( 'invalid argument. Index argument is out-of-bounds. Value: `%u`.', idx ) );
 		}
@@ -748,7 +797,7 @@
 			// We need to copy source values...
 			tmp = new Uint32Array( sbuf.length );
 			for ( i = 0; i < sbuf.length; i++ ) {
 				tmp[ i ] = sbuf[ i ]; // TODO: handle accessor arrays
 			}
 			sbuf = tmp;
 		}