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# Mostly Safe Casts

> Return a list of ndarray [data types][@stdlib/ndarray/dtypes] to which a provided ndarray [data type][@stdlib/ndarray/dtypes] can be safely cast and, for floating-point data types, can be downcast.

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## Usage

```javascript
var mostlySafeCasts = require( '@stdlib/ndarray/mostly-safe-casts' );
```

#### mostlySafeCasts( \[dtype] )

If provided a `dtype` argument, returns a list of ndarray [data types][@stdlib/ndarray/dtypes] to which a provided ndarray [data type][@stdlib/ndarray/dtypes] can be safely cast and, for floating-point data types, can be downcast.

```javascript
var out = mostlySafeCasts( 'float32' );
// e.g., returns [ 'float32', 'float64', ... ]
```

If not provided a `dtype` argument, the function returns a casting table.

```javascript
var out = mostlySafeCasts();
// returns {...}

var f32 = out[ 'float32' ];
// returns {...}

var v = f32[ 'float64' ];
// returns 1
```

If provided an unrecognized or unsupported `dtype`, the function returns `null`.

```javascript
var out = mostlySafeCasts( 'foo' );
// returns null
```

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## Examples

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

```javascript
var dtypes = require( '@stdlib/ndarray/dtypes' );
var mostlySafeCasts = require( '@stdlib/ndarray/mostly-safe-casts' );

// Get the list of supported ndarray data types:
var DTYPES = dtypes();

// Print the list of ndarray data types to which a data type can be cast...
var list;
var i;
for ( i = 0; i < DTYPES.length; i++ ) {
    list = mostlySafeCasts( DTYPES[ i ] );
    console.log( '%s: %s', DTYPES[ i ], list.join( ', ' ) );
}
```

</section>

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* * *

## See Also

-   <span class="package-name">[`@stdlib/ndarray/casting-modes`][@stdlib/ndarray/casting-modes]</span><span class="delimiter">: </span><span class="description">list of ndarray casting modes.</span>
-   <span class="package-name">[`@stdlib/ndarray/dtypes`][@stdlib/ndarray/dtypes]</span><span class="delimiter">: </span><span class="description">list of ndarray data types.</span>
-   <span class="package-name">[`@stdlib/ndarray/safe-casts`][@stdlib/ndarray/safe-casts]</span><span class="delimiter">: </span><span class="description">return a list of ndarray data types to which a provided ndarray data type can be safely cast.</span>
-   <span class="package-name">[`@stdlib/ndarray/same-kind-casts`][@stdlib/ndarray/same-kind-casts]</span><span class="delimiter">: </span><span class="description">return a list of ndarray data types to which a provided ndarray data type can be safely cast or cast within the same kind.</span>

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[@stdlib/ndarray/casting-modes]: https://github.com/stdlib-js/ndarray/tree/main/casting-modes

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

[@stdlib/ndarray/safe-casts]: https://github.com/stdlib-js/ndarray/tree/main/safe-casts

[@stdlib/ndarray/same-kind-casts]: https://github.com/stdlib-js/ndarray/tree/main/same-kind-casts

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