How to name variables

Question

• What rules do you use to name your variables?
• Where are single letter vars allowed?
• How much info do you put in the name?
• How about for exam

Answer 1

Updated

First off, naming depends on existing conventions, whether from language, framework, library, or project. (When in Rome...) Example: Use the jQuery style for jQuery plugins, use the Apple style for iOS apps. The former example requires more vigilance (since JavaScript can get messy and isn't automatically checked), while the latter example is simpler since the standard has been well-enforced and followed. YMMV depending on the leaders, the community, and especially the tools.

I will set aside all my naming habits to follow any existing conventions.

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In general, I follow these principles, all of which center around programming being another form of interpersonal communication through written language.

• Readability - important parts should have solid names; but these names should not be a replacement for proper documentation of intent. The test for code readability is if you can come back to it months later and still be understanding enough to not toss the entire thing upon first impression. This means avoiding abbreviation; see the case against Hungarian notation.

• Writeability - common areas and boilerplate should be kept simple (esp. if there's no IDE), so code is easier and more fun to write. This is a bit inspired by Rob Pyke's style.

• Maintainability - if I add the type to my name like arrItems, then it would suck if I changed that property to be an instance of a CustomSet class that extends Array. Type notes should be kept in documentation, and only if appropriate (for APIs and such).

• Standard, common naming - For dumb environments (text editors): Classes should be in ProperCase, variables should be short and if needed be in snake_case and functions should be in camelCase.

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For JavaScript, it's a classic case of the restraints of the language and the tools affecting naming. It helps to distinguish variables from functions through different naming, since there's no IDE to hold your hand while this and prototype and other boilerplate obscure your vision and confuse your differentiation skills. It's also not uncommon to see all the unimportant or globally-derived vars in a scope be abbreviated. The language has no import [path] as [alias];, so local vars become aliases. And then there's the slew of different whitespacing conventions. The only solution here (and anywhere, really) is proper documentation of intent (and identity).

Also, the language itself is based around function level scope and closures, so that amount of flexibility can make blocks with variables in 2+ scope levels feel very messy, so I've seen naming where _ is prepended for each level in the scope chain to the vars in that scope.