Set a consistent and readable variable name for Array#reduce accumulator variable

[tofumatt]

I pointed out (in #6782 (comment)) that we used settersAcc as the accumulator variable in some code and it wasn't obvious what it was from reading the code.

@aduth pointed out we are quite inconsistent with this variable: #6782 (comment)

It'd be nice to go through and clean these up:

1. Make them consistent
2. Put accumulator in the variable name (maybe make that the variable name suffix all the time).

[jpjjulie]

Hey,
Can I please try to work on this issue? I am new to open source and I thought I could contribute to Wordpress to start with. I will try and do my best to fix this issue. I am not sure if I can complete the entire fix but I would like to give it a try.

[lozinska]

Hi there! I'm new to GitHub and would like to work on this problem, but because I don't have enough experience me and my classmate @jpjjulie decide to work together on this issue and split the work between 2 of us. Thank you

[gziolo]

I have just merged #17893 from @lozinska, I will have a look at another PR from @jpjjulie shortly.

[aduth]

In addition to changes within the current codebase, we should want to consider how to document the coding standard.

Possible locations:

• https://developer.wordpress.org/coding-standards/wordpress-coding-standards/javascript/
• https://github.com/WordPress/gutenberg/blob/master/docs/contributors/coding-guidelines.md

Could make for a good topic of the weekly JavaScript chat.

[mburridge]

@gziolo what needs documenting here?

[gziolo]

It's all about using good names for variables, it's a very specific use case so I don't know if we need to explicitly document it. Example usage:

gutenberg/packages/blocks/src/api/registration.js

Lines 342 to 353 in 6b75d2e

	return Object.keys( settingValue ).reduce( ( accumulator, key ) => {
	if ( ! i18nSchema[ key ] ) {
	accumulator[ key ] = settingValue[ key ];
	return accumulator;
	}
	accumulator[ key ] = translateBlockSettingUsingI18nSchema(
	i18nSchema[ key ],
	settingValue[ key ],
	textdomain
	);
	return accumulator;
	}, {} );

In other places, the names can be different, but they still contain the accumulator suffix, example:

gutenberg/packages/block-editor/src/components/font-sizes/with-font-sizes.js

Lines 41 to 49 in 6b75d2e

	const fontSizeAttributeNames = fontSizeNames.reduce(
	( fontSizeAttributeNamesAccumulator, fontSizeAttributeName ) => {
	fontSizeAttributeNamesAccumulator[
	fontSizeAttributeName
	] = `custom${ upperFirst( fontSizeAttributeName ) }`;
	return fontSizeAttributeNamesAccumulator;
	},
	{}
	);

We have local coding guidelines for Gutenberg at: https://github.com/WordPress/gutenberg/blob/trunk/docs/contributors/code/coding-guidelines.md

General coding standards for JavaScript have a very short section about naming conventions at https://developer.wordpress.org/coding-standards/wordpress-coding-standards/javascript/#naming-conventions.

We could also close the ticket at this point.

[DaisyOlsen]

Thanks for the feedback, @gziolo. We'll close this for now. We can work to improve coding standard guidelines later if there seems to be a need.