Concatenate variable and function name

Question

We want to concatenate the function name and variable name. This should occur on click of a <a> tag.

How can we concatenate the function and variable name?

Issue:

we are getting error message fn_dataId() is not defined

Desired output:

fn_dataId() should be fn_some123();

What we tried

$(function() {
    $('.link').on('click', function() {
      console.log('clicked');
      var dataId = $(this).attr('data-id');
      console.log('data id - ' + dataId);
      
      // What we tried, but didn't work. 
      fn_dataId(); 
    });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<a data-id="some123" class="link">
Click here
</a>

[What is the XY Problem?](https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem) Why is this an issue? — Taplar, Aug 29 '19 at 22:41
@RokoC.Buljan Not if he's asking on behalf of his team/more than just himself :) — Mathew Thompson, Aug 29 '19 at 22:45
@RokoC.Buljan I didn't want to sound selfish that's all. It on behalf of team. :-) — usernameabc, Aug 29 '19 at 23:04
You are better off using a different model than what you are doing. — epascarello, Aug 29 '19 at 23:22

score 5 · Answer 1 · answered Aug 29 '19 at 22:44

You can concatenate strings, and use the result as a function using window["function_name"](args);:

function fn_some123() {
  console.log('i have been called!');
}

$(function() {
    $('.link').on('click', function() {
      var dataId = $(this).attr('data-id');
      window['fn_' + dataId]();
    });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<a data-id="some123" class="link">
Click here
</a>

I_Adze · Accepted Answer · 2019-08-29T22:48:08.050

-2

I'm not sure the use case of this it sounds like the dataId might be better off as an argument to a more generic function, but you can possibly solve it using the following:

eval("fn_" + dataId + "()")

Be wary of eval though - executing anything you take as input from a user is a big security risk

edited Aug 29 '19 at 22:48

answered Aug 29 '19 at 22:46

I_Adze

89
1
7

`eval` is something you should forget even exists. You know, you hit a bus and than you learn to avoid the bus... and you walk... and you're happy... – Roko C. Buljan Aug 29 '19 at 22:48

Concatenate variable and function name

2 Answers2