Uncaught TypeError: Cannot read property 'indexOf' of undefined in javascript

Question

var id    = $('.getval_'+product_id+''+index+'').attr("id");
var value = "";

console.log(id);
//data that return by id
6059
s2id_6061
6122
s2id_8410

if (id.indexOf('s2id_') > 0) {
    value = $('.getval_'+product_id+''+index+'').select2('val');
}else{      
    value = $('.getval_'+product_id+''+index+'').val();
}

Question: The code above is show that when the ID return by jquery, then it will show a list of data, so what I want is when the ID return, if the in front of ID don't have s2id_ it will go else statement. But the code return an error which is (Uncaught TypeError: Cannot read property 'indexOf' of undefined)

+''? This is not needed at any point in your code.

nnnnnn
– nnnnnn

2017-06-09 03:04:34 +00:00
Commented Jun 9, 2017 at 3:04 — nnnnnn
– nnnnnn, Commented Jun 9, 2017 at 3:04

Obsidian Age · Accepted Answer · 2017-06-09 03:32:28Z

4

You need to check whether id itself is set, and there are two ways of going about this.

Either chain the if (id.indexOf('s2id_') > 0) condition inside an outer if condition that checks for id:

if (id) {
    if (id.indexOf('s2id_') > 0) {
        value = $('.getval_'+product_id+''+index+'').select2('val');
    }else{      
        value = $('.getval_'+product_id+''+index+'').val();
    }
}

Or check for both conditions with an and statement:

if (id && id.indexOf('s2id_') > 0) {
    value = $('.getval_'+product_id+''+index+'').select2('val');
}else{      
    value = $('.getval_'+product_id+''+index+'').val();
}

Hope this helps! :)

edited Jun 9, 2017 at 3:32

answered Jun 9, 2017 at 3:03

Obsidian Age

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5 Comments

ASR Over a year ago

if (&& id.indexOf('s2id_') > 0) this should be if (id.indexOf('s2id_') > 0)

Obsidian Age Over a year ago

It's important to check id as well -- if you check for it and it is not set, the if condition won't be triggered. If you don't check for id and it is not set, it will attempt to check for id.indexOf(), and will throw an error because id is undefined.

Mark Over a year ago

@ObsidianAge He means you have a typo in your first example? am not sure

ASR Over a year ago

@ObsidianAge I mean you have an extra '&&' on your answer

Obsidian Age Over a year ago

Oh, I see. I did indeed. Was looking at the wrong one of the two examples ;) Well spotted!

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