Prevent JSHint warning that 'functionName is defined but never used'

Question

I have just started using JSHint (through the Sublime-Linter package for Sublime Text 2). I would like to suppress its warnings regarding functions that are used before they are defined, as I see no problem with using function definitions like this. For example, the following code generates warnings:

(function($){ 

    $(document).ready(function()
    {
      formValidationSetup();
      refreshErrorMessages();
    });

    function formValidationSetup()
    {

    }

    function refreshErrorMessages()
    {

    }

})(jQuery);

The warnings:

formValidationSetup is defined but never used

refreshErrorMessages is defined but never used

I've tried setting undef to false in the JSHint options, but I'm still getting these errors. Is there another option I should be setting? Form the JSLint docs for undef:

true if variables and functions need not be declared before used. This is not available in strict mode.

You should take that as a hint to define the functions before the event. Not that it matters technically, but it's easier to understand the code that way. — Markus Unterwaditzer, Sep 26 '12 at 17:37
Surely that's just a matter of preference. I find it easier to understand like this as there is less code. — Undistraction, Sep 26 '12 at 17:55
How is there more code if you just move the function definitions to the top? — Markus Unterwaditzer, Sep 26 '12 at 19:00
Sorry. Misunderstood you. You're right. Same amount of code. Just more logical to me to have the initialiser first. — Undistraction, Sep 26 '12 at 19:34

Roland Puntaier · Accepted Answer · 2013-09-26T15:54:18.097

91

To avoid the warning

defined but never used

in jslint in your javascript add comments like:

 /*exported formValidationSetup, refreshErrorMessages */

In jshint and jslint you can set the unused option to false:

 /*jshint unused:false*/

See Options

edited Sep 26 '13 at 15:54

answered Sep 26 '13 at 15:45

Roland Puntaier

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7

What about all the other unused variables? `unused:false` from my understanding will cause it to ignore _all_ unused behaviour. I don't think this is what's trying to be achieved. – Mohamed Bana Jul 16 '14 at 14:59
7

`// jshint ignore:line` will ignore that one line. – Michael Cole Feb 24 '15 at 07:24
1

unused is not valid in jslint – DPM Dec 04 '17 at 15:00

score 9 · Answer 2 · answered Feb 24 '15 at 07:39

I had this problem with should and expect in Chai tests. I ended up with this pattern:

'use strict';

var request = require('supertest');
var should = require('chai').should();  // jshint ignore:line
var expect = require('chai').expect;    // jshint ignore:line

process.env.NODE_ENV = 'test';
var appPromise = require('./index');

describe('GET /r_u_up', function() {

  it('respond with 204', function(done) {
    appPromise.then(function(app) {
      request(app)
      .get('/r_u_up')
      .expect(204, done);
    });
  });

});

Superior answer. Thank you. – Ken Ingram Jan 04 '17 at 02:12 — Ken Ingram, Jan 04 '17 at 02:12

score 5 · Answer 3 · answered Mar 19 '15 at 14:47

5

You can simply use

"unused": false,

in your .jshintrc

answered Mar 19 '15 at 14:47

Imal Hasaranga Perera

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score 3 · Answer 4 · answered Sep 26 '12 at 20:26

3

Interestingly, adding 'use strict'; inside the IIFE suppresses the error. Not sure why though.

answered Sep 26 '12 at 20:26

Undistraction

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score 3 · Answer 5 · edited Aug 25 '14 at 03:16

3

A better way not touching the Gruntfile.js in a typical Yoeman setup is to edit the .jshintrc file (a hidden file in Unix system). And update the content as the following:

{
  "curly": true,
  "eqeqeq": true,
  "immed": true,
  "latedef": true,
  "newcap": true,
  "noarg": true,
  "sub": true,
  "undef": true,
  "unused": false, // the change is here
  "boss": true,
  "eqnull": true,
  "node": true
}

set the "unused" to false.

edited Aug 25 '14 at 03:16

sampathsris

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answered Aug 25 '14 at 02:55

xptest18

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Welcome to Stack Overflow. Consider formatting code elements in your answer using indented code blocks or preformatted text: http://stackoverflow.com/editing-help#code – sampathsris Aug 25 '14 at 03:04

score -1 · Answer 6 · answered Mar 05 '13 at 20:13

-1

You'll want to use the 'latedef' option

answered Mar 05 '13 at 20:13

cyberwombat

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Prevent JSHint warning that 'functionName is defined but never used'

6 Answers6

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