I want to use a logic like this that does not work, why not working

Question

var a = '1==2';
if( a )
{
    alert(1);

} else {
    alert(2);

}

My Code

var arr_logic = {};
arr_logic['rst_content_padding'] = ['rst_general_wrapper', '1==2'];
$.each(arr_logic, function(i, val) {
  if (val[1]) {
    alert(1);
  } else {
    alert(2);
  }
});

remove quotes, i.e `a = 1==2` – Satpal Jun 13 '17 at 10:15 — Satpal, Jun 13 '17 at 10:15

score 0 · Answer 1 · answered Jun 13 '17 at 10:15

0

Dont put your boolean in a string :

var a = 1==2;
if( a )
{
    alert(1);

} else {
    alert(2);

}

answered Jun 13 '17 at 10:15

Zenoo

12,670
4
45
69

var arr_logic = {}; arr_logic['rst_content_padding'] = ['rst_general_wrapper', '1==2']; $.each( arr_logic, function( i, val ) { if( val[1] ) { alert(1); } else { alert(2); } }); – Nguyễn Văn Thiên Jun 13 '17 at 10:23

score 0 · Answer 2 · answered Jun 13 '17 at 10:17

0

just change your code to this :

var a = (1==2);
if( a )
{
    alert(1);
} else {
   alert(2);
}

answered Jun 13 '17 at 10:17

Emad Dehnavi

3,262
4
19
44

var arr_logic = {}; arr_logic['rst_content_padding'] = ['rst_general_wrapper', '1==2']; $.each( arr_logic, function( i, val ) { if( val[1] ) { alert(1); } else { alert(2); } });help me – Nguyễn Văn Thiên Jun 13 '17 at 10:29

score 0 · Answer 3 · answered Jun 13 '17 at 10:20

0

Non-empty string in JavaScript are truthy, which means their value is true when evaluated in a boolean context (the if statement tries to get a boolean value out of the expression you give to it).

To actually evaluate the expression itself, you must not put it in quotes to create a string, but just leave it without the quotes: 1==2. JavaScript now evaluates this expression to false (because 1 is not equal to 2), and will alert 2:

var a = 1==2;
if (a) {
  alert(1);
} else {
  alert(2);
}

By the way, in most cases, you should use the identity operator to check if two values are equal: 1 === 2 instead of 1 == 2.

answered Jun 13 '17 at 10:20

PeterMader

6,987
1
21
31

var arr_logic = {}; arr_logic['rst_content_padding'] = ['rst_general_wrapper', '1==2']; $.each( arr_logic, function( i, val ) { if( val[1] ) { alert(1); } else { alert(2); } }); help me – Nguyễn Văn Thiên Jun 13 '17 at 10:29
What's the problem? Consider asking a new SO question. – PeterMader Jun 13 '17 at 11:27

score 0 · Answer 4 · answered Jun 13 '17 at 10:29

0

Hi you can convert String to executable code in JavaScript by using eval()

var a = '1==2';
if( eval(a) )
{
    alert(1);

} else {
    alert(2);

}

answered Jun 13 '17 at 10:29

Hardik Leuwa

3,282
3
14
28

Eval ... is evil! – PeterMader Jun 13 '17 at 11:28
[This](https://stackoverflow.com/questions/86513/why-is-using-the-javascript-eval-function-a-bad-idea) SO question explains a few reasons why to not use eval. – PeterMader Jun 13 '17 at 12:16

score 0 · Answer 5 · answered Jun 13 '17 at 13:10

All you are missing is including a jQuery Library.

Include it from any of the CDN like code.jQuery or googleapis

Try this snippet.

var arr_logic = {};
arr_logic['rst_content_padding'] = ['rst_general_wrapper', 1==2];
$.each(arr_logic, function(i, val) {
  if (val[1]) {
    alert(1);
  } else {
    alert(2);
  }
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

I want to use a logic like this that does not work, why not working

5 Answers5