# pattern.is()

The `pattern.is()` function checks whether the [`$value`](#usdvalue) is a map pattern.

{% code lineNumbers="true" %}

```scss
// Sass.
@use 'sass:list';
@use 'sass:map';

// The `pattern.is()` function.
@function is($value, $pattern: map.values($pattern)) {
  @if type-of($value) == string {
    @each $pattern in $pattern {
      @if type-of($pattern) == list {
        @each $sub-pattern in $pattern {
          @if string.index($value, $sub-pattern) {
            @return true;
          }
        }
      } @else {
        @if string.index($value, $pattern) {
          @return true;
        }
      }
    }
  }
  @return false;
}
```

{% endcode %}

{% embed url="<https://github.com/angular-package/sass/blob/main/map/pattern/_pattern.is.function.scss>" %}

### Parameters

#### `$value`

A value to check against it's a pattern.

#### `$pattern: map.values($pattern)`

A list of patterns to check.

### Return

The return value is a `bool` indicating the [`$value`](#usdvalue) is a pattern of [`$pattern`](#usdpattern-map.values-usdpattern).

## Examples

```scss
// Use.
@use '@angular-package/sass/map/pattern';

// Examples.
@debug pattern.is('*.palette'); // true
@debug pattern.is('value:string'); // true
@debug pattern.is('key:number'); // true

```