feat: add ndarray/fill-slice-by

lib/node_modules/@stdlib/ndarray/fill-slice-by/README.md

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+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2025 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.
+
+-->
+
+# fillSliceBy
+
+> Fill an input [ndarray][@stdlib/ndarray/ctor] view according to a callback function.
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var fillSliceBy = require( '@stdlib/ndarray/fill-slice-by' );
+```
+
+#### fillSliceBy( x, ...s\[, options], fcn\[, thisArg] )
+
+Fills an input [ndarray][@stdlib/ndarray/ctor] view according to a callback function.
+
+```javascript
+var zeros = require( '@stdlib/ndarray/zeros' );
+var Slice = require( '@stdlib/slice/ctor' );
+var MultiSlice = require( '@stdlib/slice/multi' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function fcn( value ) {
+    return value + 10.0;
+}
+
+var x = zeros( [ 3, 4 ], {
+    'dtype': 'float64'
+});
+
+// Define the slice region:
+var s0 = new Slice( 1, 3 );
+var s1 = new Slice( 2, 4 );
+var s = new MultiSlice( s0, s1 );
+
+var y = fillSliceBy( x, s, fcn );
+// returns <ndarray>
+
+var bool = ( y === x );
+// returns true
+
+var arr = ndarray2array( y );
+// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 10.0, 10.0 ], [ 0.0, 0.0, 10.0, 10.0 ] ]
+```
+
+The function accepts the following arguments:
+
+-   **x**: array-like object containing an input [ndarray][@stdlib/ndarray/ctor].
+-   **s**: a [`MultiSlice`][@stdlib/slice/multi] instance, an array of slice arguments, or slice arguments as separate arguments.
+-   **options**: function options.
+-   **fcn**: callback function.
+-   **thisArg**: callback function execution context (_optional_).
+
+The function supports three (mutually exclusive) means for providing slice arguments:
+
+1.  providing a single [`MultiSlice`][@stdlib/slice/multi] instance.
+2.  providing a single array of slice arguments.
+3.  providing slice arguments as separate arguments.
+
+The following example demonstrates each invocation style achieving equivalent results.
+
+```javascript
+var zeros = require( '@stdlib/ndarray/zeros' );
+var MultiSlice = require( '@stdlib/slice/multi' );
+var Slice = require( '@stdlib/slice/ctor' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function clbk() {
+    return 5.0;
+}
+
+var opts = {
+    'dtype': 'float64'
+};
+
+// 1. Using a MultiSlice:
+var x = zeros( [ 3, 4 ], opts );
+
+var s0 = new Slice( 1, 3 );
+var s1 = new Slice( 2, 4 );
+var s = new MultiSlice( s0, s1 );
+
+var out = fillSliceBy( x, s, clbk );
+// returns <ndarray>
+
+var arr = ndarray2array( out );
+// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 5.0, 5.0 ], [ 0.0, 0.0, 5.0, 5.0 ] ]
+
+// 2. Using an array of slice arguments:
+x = zeros( [ 3, 4 ], opts );
+
+s0 = new Slice( 1, 3 );
+s1 = new Slice( 2, 4 );
+s = new MultiSlice( s0, s1 );
+
+out = fillSliceBy( x, [ s0, s1 ], clbk );
+// returns <ndarray>
+
+arr = ndarray2array( out );
+// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 5.0, 5.0 ], [ 0.0, 0.0, 5.0, 5.0 ] ]
+
+// 3. Providing separate arguments:
+x = zeros( [ 3, 4 ], opts );
+
+s0 = new Slice( 1, 3 );
+s1 = new Slice( 2, 4 );
+s = new MultiSlice( s0, s1 );
+
+out = fillSliceBy( x, s0, s1, clbk );
+// returns <ndarray>
+
+arr = ndarray2array( out );
+// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 5.0, 5.0 ], [ 0.0, 0.0, 5.0, 5.0 ] ]
+```
+
+The function supports the following options:
+
+-   **strict**: boolean indicating whether to enforce strict bounds checking.
+
+By default, the function throws an error when provided a slice which exceeds array bounds. To ignore slice indices exceeding array bounds, set the `strict` option to `false`.
+
+```javascript
+var zeros = require( '@stdlib/ndarray/zeros' );
+var MultiSlice = require( '@stdlib/slice/multi' );
+var Slice = require( '@stdlib/slice/ctor' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function clbk() {
+    return 5.0;
+}
+
+var x = zeros( [ 3, 4 ], {
+    'dtype': 'float64'
+});
+
+// Define the fill region:
+var s0 = new Slice( 1, null, 1 );
+var s1 = new Slice( 10, 20, 1 );
+var s = new MultiSlice( s0, s1 );
+
+var opts = {
+    'strict': false
+};
+
+// Fill the region with a scalar value:
+var y = fillSliceBy( x, s, opts, clbk );
+// returns <ndarray>
+
+var arr = ndarray2array( x );
+// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 0.0, 0.0 ] ]
+```
+
+To set the callback function execution context, provide a `thisArg`.
+
+<!-- eslint-disable no-invalid-this -->
+
+```javascript
+var zeros = require( '@stdlib/ndarray/zeros' );
+var Slice = require( '@stdlib/slice/ctor' );
+var MultiSlice = require( '@stdlib/slice/multi' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function fcn( value ) {
+    return value + this.factor;
+}
+
+var x = zeros( [ 3, 4 ], {
+    'dtype': 'float64'
+});
+
+var ctx = {
+    'factor': 10.0
+};
+
+// Define the slice region:
+var s0 = new Slice( 1, 3 );
+var s1 = new Slice( 2, 4 );
+var s = new MultiSlice( s0, s1 );
+
+var y = fillSliceBy( x, s, fcn, ctx );
+// returns <ndarray>
+
+var arr = ndarray2array( y );
+// returns [ [ 0.0, 0.0, 0.0, 0.0 ], [ 0.0, 0.0, 10.0, 10.0 ], [ 0.0, 0.0, 10.0, 10.0 ] ]
+```
+
+The callback function is provided the following arguments:
+
+-   **value**: current array element.
+-   **indices**: current array element indices.
+-   **arr**: the input [ndarray][@stdlib/ndarray/ctor].
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   An input [ndarray][@stdlib/ndarray/ctor] **must** be writable. If provided a **read-only** [ndarray][@stdlib/ndarray/ctor], the function throws an error.
+-   A **slice argument** must be either a [`Slice`][@stdlib/slice/ctor], an integer, `null`, or `undefined`.
+-   The function **mutates** the input [ndarray][@stdlib/ndarray/ctor].
+-   The function assumes that each element in the underlying input [ndarray][@stdlib/ndarray/ctor] data buffer has one, and only one, corresponding element in input [ndarray][@stdlib/ndarray/ctor] view (i.e., a provided [ndarray][@stdlib/ndarray/ctor] is not a broadcasted [ndarray][@stdlib/ndarray/ctor] view).
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var zeros = require( '@stdlib/ndarray/zeros' );
+var MultiSlice = require( '@stdlib/slice/multi' );
+var Slice = require( '@stdlib/slice/ctor' );
+var fillSliceBy = require( '@stdlib/ndarray/fill-slice-by' );
+
+// Create a zero-filled ndarray:
+var x = zeros( [ 2, 3, 4 ], {
+    'dtype': 'generic'
+});
+console.log( ndarray2array( x ) );
+
+// Specify the slice region:
+var s0 = new Slice( 1, 2 );
+var s1 = new Slice( null, null );
+var s2 = new Slice( 2, 4 );
+var s = new MultiSlice( s0, s1, s2 );
+
+// Fill the slice:
+fillSliceBy( x, s, discreteUniform( -100, 100 ) );
+console.log( ndarray2array( x ) );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<section class="links">
+
+[@stdlib/slice/multi]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/slice/multi
+
+[@stdlib/slice/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/slice/ctor
+
+[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/ctor
+
+<!-- <related-links> -->
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->