> For the complete documentation index, see [llms.txt](https://aup.nomi.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://aup.nomi.dev/the-language/collections/map/apis.md).

# APIs

## Properties

### .length

#### Getter

Return number of element in map

```javascript
var trans = { en: 'Hello', vi: 'Xin chào' }
puts 'We have ' + trans.length + 'translations'
```

### .keys

#### Getter

Return array of keys in map

```javascript
var tup = { a: 4, b: 5 }
puts tup.keys    // [a, b]
```

## Methods

### .has(key)

Check if a key exists in map

#### Parameters (1)

`key` : A key for checking

#### Return value

This method returns `true` if the key has existed, otherwise is `false`.

```javascript
var threeDee = true
var point = { x: 20, y: 50 }

if threeDee && !point.has('z') {
    point['z'] = 100
}

puts point    // { x: 20, y: 50, z: 100 }
```

### .get(key)

### .set(key, value)