disallow require calls to be mixed with regular variable declarations (no-mixed-requires)

This rule was deprecated in ESLint v7.0.0. Please use the corresponding rule in eslint-plugin-node.

In the Node.js community it is often customary to separate initializations with calls to require modules from other variable declarations, sometimes also grouping them by the type of module. This rule helps you enforce this convention.

Rule Details

When this rule is enabled, each var statement must satisfy the following conditions:

This rule distinguishes between six kinds of variable declaration types:

In this document, the first four types are summed up under the term require declaration.

var fs = require('fs'),        // "core"     \
    async = require('async'),  // "module"   |- these are "require declaration"s
    foo = require('./foo'),    // "file"     |
    bar = require(getName()),  // "computed" /
    baz = 42,                  // "other"
    bam;                       // "uninitialized"

Options

This rule can have an object literal option whose two properties have false values by default.

Configuring this rule with one boolean option true is deprecated.

Examples of incorrect code for this rule with the default { "grouping": false, "allowCall": false } options:

/*eslint no-mixed-requires: "error"*/

var fs = require('fs'),
    i = 0;

var async = require('async'),
    debug = require('diagnostics').someFunction('my-module'),
    eslint = require('eslint');

Examples of correct code for this rule with the default { "grouping": false, "allowCall": false } options:

/*eslint no-mixed-requires: "error"*/

// only require declarations (grouping off)
var eventEmitter = require('events').EventEmitter,
    myUtils = require('./utils'),
    util = require('util'),
    bar = require(getBarModuleName());

// only non-require declarations
var foo = 42,
    bar = 'baz';

// always valid regardless of grouping because all declarations are of the same type
var foo = require('foo' + VERSION),
    bar = require(getBarModuleName()),
    baz = require();

grouping

Examples of incorrect code for this rule with the { "grouping": true } option:

/*eslint no-mixed-requires: ["error", { "grouping": true }]*/

// invalid because of mixed types "core" and "module"
var fs = require('fs'),
    async = require('async');

// invalid because of mixed types "file" and "unknown"
var foo = require('foo'),
    bar = require(getBarModuleName());

allowCall

Examples of incorrect code for this rule with the { "allowCall": true } option:

/*eslint no-mixed-requires: ["error", { "allowCall": true }]*/

var async = require('async'),
    debug = require('diagnostics').someFunction('my-module'), /* allowCall doesn't allow calling any function */
    eslint = require('eslint');

Examples of correct code for this rule with the { "allowCall": true } option:

/*eslint no-mixed-requires: ["error", { "allowCall": true }]*/

var async = require('async'),
    debug = require('diagnostics')('my-module'),
    eslint = require('eslint');

Known Limitations

When Not To Use It

If you use a pattern such as UMD where the required modules are not loaded in variable declarations, this rule will obviously do nothing for you.

Version

This rule was introduced in ESLint 0.0.9.

Resources