feat: add ndarray/first

lib/node_modules/@stdlib/ndarray/first/README.md

@@ -0,0 +1,171 @@
+<!--
+
+@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.
+
+-->
+
+# first
+
+> Return a read-only view of the first element (or subarray) along one or more [`ndarray`][@stdlib/ndarray/ctor] dimensions.
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro section element. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- Package usage documentation. -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var first = require( '@stdlib/ndarray/first' );
+```
+
+#### first( x\[, options] )
+
+Returns a read-only view of the first element (or subarray) along one or more [`ndarray`][@stdlib/ndarray/ctor] dimensions.
+
+```javascript
+var array = require( '@stdlib/ndarray/array' );
+
+var x = array( [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] );
+// returns <ndarray>[ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ]
+
+var v = first( x );
+// returns <ndarray>[ 1.0 ]
+```
+
+The function accepts the following arguments:
+
+-   **x**: input [`ndarray`][@stdlib/ndarray/ctor].
+-   **options**: function options.
+
+The function accepts the following `options`:
+
+-   **dims**: list of dimensions over which to perform the operation. If a dimension index is provided as an integer less than zero, the dimension index is resolved relative to the last dimension, with the last dimension corresponding to the value `-1`. By default, the function performs the operation over all dimensions.
+
+To resolve the first element (or subarray) along one or more specified dimensions, provide a `dims` option:
+
+```javascript
+var array = require( '@stdlib/ndarray/array' );
+
+var x = array( [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] );
+// returns <ndarray>[ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ]
+
+// First column:
+var v = first( x, {
+    'dims': [ -1 ]
+});
+// returns <ndarray>[ 1.0, 3.0 ]
+
+// First row:
+v = first( x, {
+    'dims': [ -2 ]
+});
+// returns <ndarray>[ 1.0, 2.0 ]
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+## Notes
+
+-   The function always returns a **read-only** view. To convert a returned view to a writable [`ndarray`][@stdlib/ndarray/ctor], copy the contents to a new [`ndarray`][@stdlib/ndarray/ctor] (e.g., via [`@stdlib/ndarray/copy`][@stdlib/ndarray/copy]).
+-   If provided an empty `dims` array, the function returns a read-only view of the input [`ndarray`][@stdlib/ndarray/ctor].
+
+</section>
+
+<!-- /.notes -->
+
+<!-- Package usage examples. -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var uniform = require( '@stdlib/random/uniform' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var first = require( '@stdlib/ndarray/first' );
+
+var x = uniform( [ 3, 3, 3 ], -10.0, 10.0 );
+console.log( ndarray2array( x ) );
+
+// First scalar element:
+var v = first( x );
+console.log( v.get() );
+
+// First columns along the innermost dimension:
+v = first( x, {
+    'dims': [ -1 ]
+});
+console.log( ndarray2array( v ) );
+
+// First matrix along the outermost dimension:
+v = first( x, {
+    'dims': [ 0 ]
+});
+console.log( ndarray2array( v ) );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="references">
+
+</section>
+
+<!-- /.references -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/ctor
+
+[@stdlib/ndarray/copy]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/copy
+
+<!-- <related-links> -->
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->