Question

I used the code described here but now, when I do a “for … in …” cicle, it gets the function “indexOf” as an index position of the array…

Example Code:

var the_array=new Array();                  
for (key in the_array){
    console.log(key +"  -  "+the_array[key]);
} 

This code shows this in the console:

indexOf  -  function (searchElement /*, fromIndex */ ) {  
    "use strict";  
    if (this == null) {  
       throw new TypeError();  
    }  
    var t = Object(this);  
    var len = t.length >>> 0;  
    if (len === 0) {  
        return -1;  
    }  
    var n = 0;  
    if (arguments.length > 0) {  
        n = Number(arguments[1]);  
        if (n != n) { // shortcut for verifying if it's NaN  
            n = 0;  
        } else if (n != 0 && n != Infinity && n != -Infinity) {  
            n = (n > 0 || -1) * Math.floor(Math.abs(n));  
        }  
    }  
    if (n >= len) {  
        return -1;  
    }  
    var k = n >= 0 ? n : Math.max(len - Math.abs(n), 0);  
    for (; k < len; k++) {  
        if (k in t && t[k] === searchElement) {  
            return k;  
        }  
    }  
    return -1;  
}

How could I prevent the function from appearing as a key on the array?

Btw, I know that I can use the inArray function of jquery but, in this case, I would like to use the “indexOf” function…

Answer 1

It’s a bad idea to use for...in on arrays, for this and other reasons. See my answer here:

Why is 'for(var item in list)' with arrays considered bad practice in JavaScript?