Disallow Initializing to undefined (no-undef-init)
In JavaScript, a variable that is declared and not initialized to any value automatically gets the value of undefined
. For example:
var foo;
console.log(foo === undefined); // true
It’s therefore unnecessary to initialize a variable to undefined
, such as:
var foo = undefined;
It’s considered a best practice to avoid initializing variables to undefined
.
Rule Details
This rule aims to eliminate variable declarations that initialize to undefined
.
The following patterns are considered warnings:
var foo = undefined;
let bar = undefined;
The following patterns are not warnings:
var foo;
let bar;
When Not To Use It
If you want to allow initialization of variables with undefined
, then you can safely turn this rule off.
Related Rules
Version
This rule was introduced in ESLint 0.0.6.