JS: Array.prototype.keys
New in JS2015.
myArray.keys()
-
Return a Iterator (also is a Iterable Object), each entry is the index of the array.
Array.from(["a", "b", "c"].keys(), (x) => { console.log(x); }); /* 0 1 2 */
Example
This example shows the result is iterator and iterable:
const xx = ["a", "b", "c"].keys(); // is a iterator console.log(Object.prototype.toString.call(xx) === "[object Array Iterator]"); // is also a iterable console.log(Symbol.iterator in xx);
JS Array.prototype Properties
- JS: Array.prototype.at
- JS: Array.prototype.concat
- JS: Array.prototype.constructor
- JS: Array.prototype.copyWithin
- JS: Array.prototype.entries
- JS: Array.prototype.every
- JS: Array.prototype.fill
- JS: Array.prototype.filter
- JS: Array.prototype.find
- JS: Array.prototype.findIndex
- JS: Array.prototype.findLast
- JS: Array.prototype.findLastIndex
- JS: Array.prototype.flatMap
- JS: Array.prototype.flat (Flatten Array)
- JS: Array.prototype.forEach
- JS: Array.prototype.includes
- JS: Array.prototype.indexOf
- JS: Array.prototype.join
- JS: Array.prototype.keys
- JS: Array.prototype.lastIndexOf
- JS: Array.prototype.length
- JS: Array.prototype.map
- JS: Array.prototype.pop
- JS: Array.prototype.push
- JS: Array.prototype.reduce
- JS: Array.prototype.reduceRight
- JS: Array.prototype.reverse
- JS: Array.prototype.shift
- JS: Array.prototype.slice
- JS: Array.prototype.some
- JS: Array.prototype.sort
- JS: Array.prototype.splice
- JS: Array.prototype.toReversed
- JS: Array.prototype.toSorted
- JS: Array.prototype.toSpliced
- JS: Array.prototype.toString
- JS: Array.prototype.unshift
- JS: Array.prototype.values
- JS: Array.prototype.with