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# WeakMap.prototype.has()

The **`has()`** method returns a boolean indicating whether an
element with the specified key exists in the `WeakMap` object or not.

## Syntax

```js
has(key)
```

### Parameters

- `key`
  - : Required. The key of the element to test for presence in the `WeakMap`
    object.

### Return value

- Boolean
  - : Returns `true` if an element with the specified key exists in the
    `WeakMap` object; otherwise `false`.
