JavaScript: Map.prototype.forEach
New in JS2015.
map_obj.forEach(f)
-
Apply function f to all entries in map map_obj in the order the entries are inserted. Does not modify the map object. Return
undefined
.
f is passed 3 arguments: value, key, map_obj. Note the order in parameter is value first. map_obj.forEach(f, thisArg)
-
Use thisArg for this Binding of f. If it is not given,
undefined
is used.
const mm = new Map( [["a", 1], ["b",2] ]); const rr = mm.forEach( (v,k) => { console.log(v, k); } ); // prints // 1 'a' // 2 'b' // returns undefined console.log( rr === undefined ); // true
See also: Iterate Over Map Object