Make IIFE wrap inside to avoid conflict with no-extra-parens

[marlowpayne]

Status: Ready for Review
Reviewers: @donnielrt @Helen-Mobify

Changes

• Our current wrap-iife rule defaults to "outside" wrapping required

// wrapping the call expression (outside)
return (function () { return { y: 1 };}());

However, this will conflict with our rule for no-extra-parens, and since the rule is set to "outside" we cannot avoid a linting error since wrapping via inside to avoid no-extra-parens i.e.

// wrapping the function expression (inside)
return (function () { return { y: 1 };})();

will violate the default "outside" rule.
This PR changes our rule to "inside" wrapping so that we may reach a no lint error state.

TL;DR: With the "outside" IIFE wrapping rule, you'll always be in an error state. Changing the IIFE rule to "inside" will let us reach a conflict-free state with no lint errors.

Todos:

• Engineer +1

Links:

Eslint wrap-iife rule

How to Test

• Verify that we enter a constant lint error state for IIFEs
• Update your local copy of the code-style by running npm install -g git+ssh://git@github.com:mobify/mobify-code-style.git#wrap-iife-conflict
• Verify that we may now wrap IIFEs via "inside" parens, to avoid linting errors

[donnielrt]

@marlowpayne I'm a little confused, we don't seem to be getting a lint error for the outside wrapping of the IIFE:

Am I misunderstanding what you're saying?

[marlowpayne]

Ah sorry @donnielrt I grabbed those code samples from the Eslint site, not realizing that my cause for the PR is a bit more specific. Try the IIFE in a return statement.

// wrapping the call expression (outside)
return (function() { return { y: 1 };}());

[marlowpayne]

It's been a while since anyone's looked at this. Mind taking a quick look, @Helen-Mobify ?

[wizardlyhel]

@marlowpayne

I do see the error for the code example you have.

However, even with this updated mobify-code-style branch, I don't see error disappear.

[marlowpayne]

@Helen-Mobify thanks for taking a look. On this branch you should be able to reach a non-error state for "inside" wrapping IIFEs. Are you able to get a non-error state with this?:

test: function() {
    return (function () { return { y: 1 };})();
}

[wizardlyhel]

@marlowpayne The screenshot I included are the errors I got for that piece of code.

[wizardlyhel]

👍 Tested!

The working code is to have the wrapping inside.

return (function() { return { y: 1 };})();