# map.retrieve()

The `map.retrieve()` function retrieves a value from [`$map`](#usdmap) by a [`$method`](#usdmethod) get or pick with a [`$key`](#usdkey).

{% code lineNumbers="true" %}

```scss
// Functions.
@use 'map.get.function' as *;
@use 'map.pick.function' as *;

// The `map.retrieve()` function.
@function retrieve($method, $map, $key, $fallback: null) {
  @return if(
    $method == get,
    get($map, $key, $fallback),
    if($method == pick, pick($map, $key...), $map or $fallback)
  );
}
```

{% endcode %}

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

### Parameters

#### `$method`

The method get(`map.get()`) or pick(`map.pick()`) used to retrieve the value.

#### `$map`

A map to get the value by using [`$method`](#usdmethod) and [`$key`](#usdkey).

#### `$key`

A key to get or pick the value from [`$map`](#usdmap).

#### `$fallback: null`

The fallback value if returned is `null`.

### Return

The return value is a retrieved value from [`$map`](#usdmap) or [`$fallback`](#usdfallback-null).

## Examples

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

// Examples.
$-dictionary-example: (
  general: (word: słowo, (wrapper, wrap): owijka, (technology, technologia): tech, color: c),
  class: (prefix: class-prefix, separator: class-separator, suffix: class-suffix, calendars: (calendar: cal), labels: (label: lab)),
  prefix: spectre,
  border: b,
  color: c,
  separator: '-',
  suffix: end,
  outline: o,
  var: (prefix: var-prefix, suffix: var-suffix)
);

@debug map.retrieve(get, $-dictionary-example, general); // (word: słowo, (wrapper, wrap): owijka, (technology, technologia): tech, color: c)
@debug map.retrieve(pick, $-dictionary-example, ((class, calendars),)); // (calendars: (calendar: cal))
@debug map.retrieve(pick, $-dictionary-example, (general, (class, calendars))); // (general: (word: słowo, (wrapper, wrap): owijka, (technology, technologia): tech, color: c), calendars: (calendar: cal))

// input list
@debug map.retrieve(pick $-dictionary-example ((class, calendars),)...); // (calendars: (calendar: cal))

// null
@debug map.retrieve(get, $-dictionary-example, test); // null
@debug map.retrieve(pick, $-dictionary-example, test); // (test: null)

```