Question

I need to search for the presence of an array inside an array. It is similar to jQuery.inArray function.

For

var a = [ [1,2], [1,3] ];
console.log(  jQuery.inArray([1,3],a  ) )

I get -1 as ans. How to do this?

Thank you

Answer 1

In V8 (that is, Chrome), there is a nifty trick: while == does not work for arrays, <= && >= does.

You can iterate and check for each item if it’s appearent:

for(var i = 0; i < a.length; i++) {
    if(a[i] >= [1, 3] && a[i] <= [1, 3]) alert(i);
}

For other browsers, you’d need a function that checks for array equality:

http://www.svendtofte.com/code/usefull_prototypes/prototypes.js

Array.prototype.compareArrays = function(arr) {
    if (this.length != arr.length) return false;
    for (var i = 0; i < arr.length; i++) {
        if (this[i].compareArrays) { //likely nested array
            if (!this[i].compareArrays(arr[i])) return false;
            else continue;
        }
        if (this[i] != arr[i]) return false;
    }
    return true;
}

Then:

for(var i = 0; i < a.length; i++) {
    if(a[i].compareArrays([1, 3])) alert(i);
}