ordered-map-extended-pmb

JS Map on steroids.

API

This module exports one function:

upgradeMap([origMap])

If origMap is false-y, operates as if origMap were a new Map(). Adds extra methods to origMap (in-place) and returns origMap. The extra methods are:

.toDict()

Return the entries as a plain old JS object.

.del(key)

Alias for .delete.

.keyList()

Return the list of keys, as a traditional Array.

.valList()

Return the list of values, as a traditional Array.

.upd(dict)

Update the map with entries from dict. Returns the map.

.weakUpd(dict)

Update the map with those entries from dict whose key did not exist in the map yet. Returns the map.

.getOrInit(key, initVal[, initFunc])

Returns the value for key if there is one. Otherwise, adds an entry for key with initial value initVal. If initFunc is truthy, the entry will instead be initialized with the result of initFunc(initVal). The value that has been set will also be returned.

.getOrInitPr(key, initVal[, initFunc])

Like .getOrInit, but supports Promises in initVal, and if initFunc is given, its result is awaited. Asynchronous initialization can cause race conditions between multiple .getOrInitPr and/or other code that might set the value while .getOrInitPr is (a)waiting. In that case, it will flinch and throw a race condition Error, which will thus be delivered as a rejected promise. Since it flinces from .set()ting its own (too late) initial value, that value usually would be lost. For cases where you do need it, it is reported on the .lostVal property of the Error.

Usage

see test/basics.mjs.

Known issues

• Needs more/better tests and docs.

License

ISC