Reputation: 39
why we use -1 in javascript for loop
the example code here
var arr = [1,2,2,3,4,5,5,5,6,7,7,8,9,10,10];
function squash(arr){
var tmp = [];
for(var i = 0; i < arr.length; i++){
if(tmp.indexOf(arr[i]) == -1){
tmp.push(arr[i]);
}
}
return tmp;
}
console.log(squash(arr));
Upvotes: 0
Views: 47
Reputation: 19264
The indexOf
function returns -1
if the item is not found in the desired array.
document.write([1, 2, 3].indexOf(1)+" "); //Exists
document.write([1, 2, 3].indexOf(0)); //Does not exist
Upvotes: 2