Avoid assignment operators in return statements

Docs > Code Analysis > Static Analysis Rules > Avoid assignment operators in return statements

This page is not yet available in Spanish. We are working on its translation.
If you have any questions or feedback about our current translation project, feel free to reach out to us!

Metadata

ID: javascript-code-style/no-return-assign

Language: JavaScript

Severity: Notice

Category: Error Prone

Description

JavaScript allows return statements to do assignment operations. Because it is hard to differentiate between an assignment and a comparison when written as part of the return statement, avoid using return statements.

Non-Compliant Code Examples

function x() { return result = a * b; };
function x() { return (result) = (a * b); };
function x() { return result = a * b; };
function x() { return (result) = (a * b); };
() => { return result = a * b; };
() => result = a * b;
function x() { return result = a * b; };
// Allow parens option not supported
// function x() { return (result = a * b); };
// function x() { return result || (result = a * b); };
function foo(){
    return a = b
}
function doSomething() {
    return foo = bar && foo > 0;
}
function doSomething() {
    return foo = function(){
        return (bar = bar1)
    }
}
function doSomething() {
    return foo = () => a
}
function doSomething() {
    return () => a = () => b
}
function foo(a){
    return function bar(b){
        return a = b
    }
}
const foo = (a) => (b) => a = b;

Compliant Code Examples

module.exports = {'a': 1};
var result = a * b;
function x() { var result = a * b; return result; }
function x() { return (result = a * b); }
function x() { var result = a * b; return result; }
function x() { return (result = a * b); }
function x() { var result = a * b; return result; }
function x() { return function y() { result = a * b }; }
() => { return (result = a * b); }
() => (result = a * b)
const foo = (a,b,c) => ((a = b), c)
function foo(){
    return (a = b)
}
function bar(){
    return function foo(){
        return (a = b) && c
    }
}
const foo = (a) => (b) => (a = b)