JavaScript.md

JavaScript Rules

Enclosed you’ll find stylistic rules and guidelines for JavaScript authors contributing code back to Medium. Following these rules will make sure that our codebase is consistent and maintainable.

Ideally, all our code should look like a single person typed it, no matter how many people contributed. If you’re editing a file, make sure your changes are consistent with the rest of the file even if it goes against some of the rules on this page.

Naming

• Use functionNamesLikeThis, variableNamesLikeThis, ClassNamesLikeThis, EnumNamesLikeThis, methodNamesLikeThis, and SYMBOLIC_CONSTANTS_LIKE_THIS.
• Private properties, variables, and methods (in files or classes) should be named with a leading underscore.
• Protected properties, variables, and methods should be named without an underscore (like public ones).
• For more information on private and protected, read the section on visibility.

Namespaces

Client code should use namespaces under obv that mirror the folder structure.

goog.provide('obv.sloth')

obv.sloth.sleep = function() {
  // ...
}

Filenames should match the namespace of class that they define, e.g. obv.foo.Class should be in /foo/Class.js and obv.bar.baz should be in /bar/baz.js. Filenames should end in .js, and should contain no punctuation except for - or _. Prefer - to _

Code formatting

• Always start your curly braces on the same line as whatever they’re opening. For example:

if (something) {
  // ...
} else {
  // ...
}

• Try not to make your lines go over 100 characters.
• Use 2-char indent for blocks and 4-char indent for wrapped lines.
• Use whitespace around operators.
• Do not put any space after [, { or before ], } in single-line array and object initializers.

var arr = [1,2,3]
var obj = {a: 1, b: 2, c: 3}

• Format multiline array and object initializers likes this:

var obj = {
  a: 1,
  b: 2,
  c: 3
}

• Do not use semicolons unless omiting one will break your code.
• Use single-quotes for strings.

Types

For client code, we use Google Closure Compiler for type checks. Annotate your functions and properties accordingly. For more information, see the JS Compiler Docs.