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

Arrays.

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# resolveGetter

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

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## Usage

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

#### resolveGetter( x )

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

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

var get = resolveGetter( x );
var v = get( x, 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 array-like object having an unsupported [data type][@stdlib/array/dtypes], the function returns a default accessor function for accessing elements from any array-like object; otherwise, the function returns an accessor function which should **only** be provided an array instance having the same data type (e.g., if provided a `Float64Array`, the returned accessor function should only be provided instances of `Float64Array`).
-   Accessor functions do **not** verify that provided input arrays are array instances having a specific data type, 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.
-   Accessor functions do **not** verify that provided input arrays implement the get/set protocol.
-   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 resolveGetter = require( '@stdlib/array/base/resolve-getter' );

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

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

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

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

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

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

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

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

arr = filled( 9, 10, 'uint8c' );
v = resolveGetter( 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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