one-dependency-per-line.md

Enforce line-break rules for AMD dependencies (one-dependency-per-line)

When more than a handful of dependencies are required in a module, the list can quickly become too long to fit on one line. Inconsistent line break usage can also make it hard to read and maintain long lists of dependencies.

Rule Details

This rule aims to enforce consistent line-break usage in dependency lists.

Options

The rule takes one option, an object, which has two keys, paths and names. These keys allow individual control over the line-break rules for, respectively, the dependency path list and the list of names (arguments) passed to the module definition function. Each key can either be a string "always" or "never", or a numeric value representing the maximum number of dependencies each list can contain before enforcing the one-dependency-per-line rule. The default is { "paths": "always", "names": "always" }.

    "one-dependency-per-line": [2, { "paths": "always", "names": "never" }]
    "one-dependency-per-line": [2, { "paths": 3, "names": 3 }]

The following examples demonstate the behavior of these options.

{ "paths": "always", "names": "always" }

When the mode is set to "always", each dependency must be placed on a separate line.

In this mode, the following pattern is considered a warning:

require(['jquery', 'underscore', 'backbone'], function ($, _, Backbone) {
    /* ... */
});

Whereas, the following pattern is not considered a warning:

require([
    'jquery',
    'underscore',
    'backbone'
], function (
    $,
    _,
    Backbone
) {
    /* ... */
});

{ "paths": "never", "names": "never" }

When the mode is set to "never", dependency lists must appear on one line.

In this mode, the following pattern is considered a warning:

require([
    'jquery',
    'underscore',
    'backbone'
], function (
    $,
    _,
    Backbone
) {
    /* ... */
});

Whereas, the following pattern is not considered a warning:

require(['jquery', 'underscore', 'backbone'], function ($, _, Backbone) {
    /* ... */
});

{ "paths": 3, "names": 3 }

When a number value is provided, it defines the maximum number of dependencies a list can contain before line-breaking is enforced for all dependencies in that list. This allows for very short dependency lists to appear on a single line, but longer ones to spaced appropriately.

In this mode, the following patterns are considered warnings:

// "one-dependency-per-line": [2, { "paths": "always", "names": 3 }]
require([
    'jquery',
    'underscore',
    'backbone',
    'some/other/module'
], function ($, _, Backbone, SomeOtherModule) {
    /* ... */
});

// "one-dependency-per-line": [2, { "paths": 2, "names": 2 }]
require(['jquery', 'underscore', 'backbone'], function ($, _, Backbone) {
    /* ... */
});

Whereas, the following patterns are not considered warnings:

// "one-dependency-per-line": [2, { "paths": "always", "names": 3 }]
require([
    'jquery',
    'underscore',
    'backbone',
    'some/other/module'
], function (
    $,
    _,
    Backbone,
    SomeOtherModule
) {
    /* ... */
});

// "one-dependency-per-line": [2, { "paths": 2, "names": 2 }]
require(['jquery', 'underscore'], function ($, _) {
    /* ... */
});

When Not To Use It

If your project will not be following any consistent line-break pattern for dependencies, it is safe to turn off this rule.

Further Reading

• Define a Module