CODEWITHSUNDEEP
javascript
YankeeCki
YankeeCki

Reputation: 41

I can't understand Array.prootype.slice.call

temp = {0:'one', 1:'two', 2:'three', 3:'four',length:4};
console.log( Array.prototype.slice.call( temp, 1));

//["two", "three", "four"]

Why is this the result? Where is the length property? Shouldn't it be ["two", "three", "four", 4] when Array.prototype.slice.call( temp, 1) is called?

Upvotes: 1

Views: 47

Answers (1)

Serge Seredenko
Serge Seredenko

Reputation: 3541

Simplified version of slice:

Array.prototype.slice = function(a, b) {
  a = a || 0
  if (a < 0) a += this.length
  b = b || this.length
  if (b < 0) b += this.length
  var ret = []
  for (var i = a; i < b; i++)
    ret.push(this[i])
  return ret
}

So actually slice function uses [] operator and .length property on this. That's how it works on arrays and array-like objects (those which have [] and .length)

Upvotes: 3

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