json index of property value

Question

I need to get the index of the json object in an array whose by the objects id

here is the example code

var list = [ { _id: \'4dd822c5e8a6c42aa7000         


        

Answer 1

function index_of(haystack, needle) {
    for (var i = 0, l = haystack.length; i < l; ++i) {
        if( haystack[i]._id === needle ) {
           return i;   
        }
    }
    return -1;
}

console.log(index_of(list, '4dd80b16e8a6c428a900007d'));

same as the above, but caches the length of the haystack.