@stdlib/array/base/getter/README.md

Arrays.

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# getter

> Return an accessor function for retrieving an element from an indexed array-like object.

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## Usage

```javascript
var getter = require( '@stdlib/array/base/getter' );
```

#### getter( dtype )

Returns an accessor function for retrieving an element from an indexed array-like object.

```javascript
var arr = [ 1, 2, 3, 4 ];

var get = getter( 'generic' );
var v = get( arr, 2 );
// returns 3
```

The returned accessor function accepts the following arguments:

-   **arr**: input array.
-   **idx**: element index.

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## Notes

-   If provided an unsupported [`dtype`][@stdlib/array/dtypes], the function returns a default accessor function for accessing elements from any indexed array-like object; otherwise, the function returns an accessor function which should **only** be provided an array instance corresponding to `dtype` (e.g., if `dtype` is `'float64'`, the returned accessor function should only be provided instances of `Float64Array`).
-   Accessor functions do **not** verify that provided input arrays are array instances corresponding to `dtype`, as doing so would introduce performance overhead. If array instances corresponding to other data types are provided to an accessor function, JavaScript runtimes will consider the function polymorphic, potentially triggering de-optimization. In order to ensure maximum performance, **always** ensure that an accessor function is monomorphic.
-   Accessor functions do **not** perform bounds checking.
-   An _indexed_ array-like object is a data structure in which one retrieves elements via integer indices using bracket `[]` notation (e.g., `Float64Array`, `Int32Array`, `Array`, etc). This is in contrast to an _accessor_ array-like object in which one retrieves elements using `get` and `set` methods (e.g., `Complex64Array` and `Complex128Array`).

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## Examples

<!-- eslint no-undef: "error" -->

```javascript
var filled = require( '@stdlib/array/filled' );
var dtype = require( '@stdlib/array/dtype' );
var getter = require( '@stdlib/array/base/getter' );

var arr = filled( 1.0, 10, 'float64' );
var v = getter( dtype( arr ) )( arr, 2 );
// returns 1.0

arr = filled( 2.0, 10, 'float32' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 2.0

arr = filled( 3, 10, 'int32' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 3

arr = filled( 4, 10, 'int16' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 4

arr = filled( 5, 10, 'int8' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 5

arr = filled( 6, 10, 'uint32' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 6

arr = filled( 7, 10, 'uint16' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 7

arr = filled( 8, 10, 'uint8' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 8

arr = filled( 9, 10, 'uint8c' );
v = getter( dtype( arr ) )( arr, 2 );
// returns 9
```

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[@stdlib/array/dtypes]: https://github.com/stdlib-js/array/tree/main/dtypes

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