add(value, key)

Adds a value for a given key to a map.

This is an alias for set(key, value) that does not have an obvious reason to exist. The purpose of this method is to allow certain generic collection methods including addEach, filter, and clone, to treat sets and maps in the same fashion, without regard for whether the keys are or not meaningful for the collection. For example, sets implement add(value), but maps implement add(value, key). Iterating a List provides meaningful indexes that can be used for keys if they are converted to maps. Consider this excerpt from addEach(values) for generic collections.

values.forEach(this.add, this);

This copies values from an abitrary collection into this one. Regardless of whether this collection is a map or a set, and whether the values come from a map or a set, add is able to bridge the gap. This is particularly important since addEach(values) is the last operation of every collection constructor.

On collections


  • add(value, key)