language-javascript.md

JavaScript

Please refer to airbnb/javascript and eslint-config-juwai for style–guides about JavaScript.

Addendum

Whitespace

Use soft tabs (space character) set to 4 spaces.

Strings

Avoid to have more than 120 characters per line.

Fix errors early.

We want to target bugs as soon as possible. To do so, we should always add 'use strict'; as the first statement of any function at the root of the document if you are not using ES6.

Be more flexible.

In case of a function doing too much but that can‘t be easily refactored, and if that function has more than two parameters, let’s avoid having the following:

/** Defining this awesome function that does too much.
 *
 * @param {integer} parameter1 - Represent something.
 * @param {integer} parameter2 - Represent something else.
 * @param {boolean} parameter3 - Is this for real?
 * @param {string}  parameter4 - Values for that other stuff.
 */
someFunctionWithAddedParametersOverTime( parameter1, parameter2, parameter3, parameter4 ) {
    // Do something…
    […]
}

// Call the function.
someFunctionWithAddedParametersOverTime(
    undefined,
    undefined,
    false,
    'someValue'
);

Use an options parameter instead to allow more flexibility:

/** Defining this awesome function that still does too much.
 *
 * @param {object}  options
 * @param {integer} options.parameter1 - Represent something.
 * @param {integer} options.parameter2 - Represent something else.
 * @param {boolean} options.parameter3 - Is this for real?
 * @param {string}  options.parameter4 - Values for that other stuff.
 */
someFunctionWithOptions( options ) {
    // Do something…
    […]
}

// Call the function.
someFunctionWithOptions({
    'parameter4' => 'someValue'
});

Ideally: refactor the function into smaller pieces.

Tools

You can use them in your environment with the relevant tools or plugins:

• ESLint: http://eslint.org/