Javascript eval() refactor

Question

I have a function like this:

function x(a,b,c) {
    eval("window.document.forms['"+ a +"']."+ b +".value = '"+ c +"'");
}

I understand why eval === evil most of the time, so what's the best way to write that function without using eval? Does the below makes sense? Why?

function x(a,b,c) {
    window.document.forms[a].b.value = c.toString();
}

Keep in mind that calling `toString` on `null` or `undefined` will throw. While original version wouldn't. — Yury Tarabanko, Jul 14 '16 at 19:50
@user1533609 because on the `eval` we can see the single `'` around the `c` variable I assumed it is converted to a string. Note I found this function on old code I'm working with. — Leandro Barbosa, Jul 14 '16 at 20:01
@Oriol makes sense to just use `document` but is this acceptable cross-browser (desktop and mobile)? — Leandro Barbosa, Jul 14 '16 at 20:03
Yes, you can access global properties as global variables and viceversa. But of course, don't shadow `document` with a more local variable. — Oriol, Jul 14 '16 at 20:04

score 1 · Accepted Answer · answered Jul 14 '16 at 19:42

1

Your above function has no reason to be using eval - use bracket notation to access an objects property via a variable:

window.document.forms[a][b].value = c.toString();

answered Jul 14 '16 at 19:42

tymeJV

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Javascript eval() refactor

1 Answers1