Add "update" function to Map #16360

lrhn · 2014-01-28T14:48:55Z

Add a method to Map that allows updating the value of an existing entry.
The operation should only do one lookup, but should otherwise work as:

V update(K key, V update(V value)) {
  this[key] = update(this[key]);
}

Optionally also allow to special case for non-existing elements:

V update(K key, V update(V value), {V ifAbsent()}) {
  V value = this[key];
  if (value == null && ifAbsent != null && !this.containsKey(key)) {
    this[key] = ifAbsent();
  } else {
    this[key] = update(value);
  }
}

lrhn added Type-Enhancement library-core area-core-library SDK core library issues (core, async, ...); use area-vm or area-web for platform specific libraries. labels Jan 28, 2014

kevmoo added type-enhancement A request for a change that isn't a bug and removed priority-unassigned labels Feb 29, 2016

lrhn added the core-m label Aug 11, 2017

floitschG added core-2 and removed core-m labels Aug 25, 2017

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Add "update" function to Map #16360

Add "update" function to Map #16360

lrhn commented Jan 28, 2014 •

edited

Add "update" function to Map #16360

Add "update" function to Map #16360

Comments

lrhn commented Jan 28, 2014 • edited

lrhn commented Jan 28, 2014 •

edited