Question

var arr = [‘test’,’hello’];

is there a javascript native call to get index of some value(‘hello’) in an array?

Answer 1

In javascript 1.6+ you can use .indexOf():

var index = arr.indexOf('hello');

In earlier versions you would just have to loop through the array yourself.

Interestingly, alert([].indexOf) in Chrome gives you the implementation:

function indexOf(element, index) {
  var length = this.length;
  if (index == null) {
    index = 0;
  } else {
    index = (_IsSmi(IS_VAR(index)) ? index : ToInteger(index));
    if (index < 0) index = length + index;
    if (index < 0) index = 0;
  }
  for (var i = index; i < length; i++) {
    var current = this[i];
    if (!(typeof(current) === 'undefined') || i in this) {
      if (current === element) return i;
    }
  }
  return -1;
}

Don’t ask me what _IsSmi(IS_VAR(index)) does though…