DefaultMap

This aims to provide a simple Map prototype with default value / value constructor.

Installation

npm install --save default-map

Usage

Requiring

var DefaultMap = require('default-map');

Initialization

Constructor signature: DefaultMap(options).

With a default value

var map = new DefaultMap({ defaultValue: 'my default value' });

With a default generator function

var map = new DefaultMap({ defaultGenerator: function (key) {
  return 'the default value for the key: ' + key;
} });

With initial data

var map = new DefaultMap({
  data: { the: 'initial data' },
  defaultValue: 'the default value'
});

Checking key existence

map.has('key');

Setting a value to a key

map.set('key', 'value');

Getting the value of key

map.get('foo');

If map has no key 'foo', it will be created using the default value / the default generator.

Deleting a key

map.delete('foo');

Getting the entry set (useful for JSON serialization)

map.toHash();

Checking if the map is empty

map.isEmpty();

Iterating over the whole entry set

map.forEach(function (value, key, iteratedMap) {
  console.log('Entry:', key, value);
}, this);

Note that:

• Giving this as the second argument of DefaultMap#forEach preserves the calling context's this.
• The third argument of the callback contains a reference to the iterated map.