Global variable origin

Question

I have an interesting problem.

I've detected global variable height in my project.
Project has hundreds of files, so height variable occurs thousands of times.
Obviously, I had forgotten var operator somewhere.

How can I track this global variable origin?

UPD:
As I already said, variable occurs thousands of times.
And I don't really know how it can look like:

// forgotten var:
height = 'something';

// or forgotten comma
var a = 1,
    b = 2 
    height = 3;

So I definitely can not search for it manually.
Any suggestions?

Possible duplicate of [How to know in which file that defined a js global var in chrome console?](http://stackoverflow.com/questions/11644937/how-to-know-in-which-file-that-defined-a-js-global-var-in-chrome-console) — FiringSquadWitness, Apr 27 '16 at 22:22
Dear @Paulpro, thank you for suggestion. Your regexp found hundreds of matches, including `some_other_height` variables too. It's not really helpful. — Legotin, Apr 27 '16 at 22:32
If you have other vairables that end in height, you can add a boundary to make it to work for you: `grep -e '\bheight\s*=`. That should find everywhere `height` is assigned a value (which is what creates an implicit global). The forgotten `var` and forgotten comma options you posted wouldn't create a global, they would throw a `ReferenceError: height is not defined`. — Paul, Apr 27 '16 at 22:34
@Paulpro this regexp definitely better, but it still found matches like `style.height`. Besides, no one said that after the variable was a "=" sign. — Legotin, Apr 27 '16 at 22:40
@legotin An equals sign is the only possible way to create a global variable accidentally. The only other way would be assigning it as a property of the global object, which would be pretty hard to do by accident. — Paul, Apr 27 '16 at 22:42
You could try `grep -e '\(^\|\s\)height\s*='`. That should also filter out the `style.height` and such. — Paul, Apr 27 '16 at 22:43
@Paulpro you're right. I've corrected cases where a it could occur. — Legotin, Apr 27 '16 at 22:44
@Paulpro you overdone with your last regexp, it finds nothing now :) — Legotin, Apr 27 '16 at 22:48
We might have differently flavours of `grep`. Maybe try: `grep -e '(^|\s)height\s*=` ? — Paul, Apr 27 '16 at 22:49

score 1 · Accepted Answer · answered Apr 28 '16 at 04:51

An equals sign is the only possible way to create a global variable accidentally. The only other way would be assigning it as a property of the global object, which wouldn't likely be done by accident. Therefore you can search through your files for assignments to height using something like this:

grep -e '(^|\s)height\s*=' -R *

From those assignments you can determine where height gets created, and what scope it needs to be declared in.

By the way, in 'use strict'; mode, JavaScript would throw an error instead of creating an implicit global, which could be more desirable.

Global variable origin

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