no-constructor-return.md

Disallow returning value in constructor (no-constructor-return)

In JavaScript, returning a value in the constructor of a class may be a mistake. Forbidding this pattern prevents mistake resulting from unfamiliarity with the language or copy-paste error.

Rule Details

This rule disallows return statements in the constructor of a class. Note that returning nothing with flow control is allowed.

Examples of incorrect code for this rule:

/*eslint no-constructor-return: "error"*/

class A {
    constructor(a) {
        this.a = a;
        return a;
    }
}

class B {
    constructor(f) {
        if (!f) {
            return 'falsy';
        }
    }
}

Examples of correct code for this rule:

/*eslint no-constructor-return: "error"*/

class C {
    constructor(c) {
        this.c = c;
    }
}

class D {
    constructor(f) {
        if (!f) {
            return;  // Flow control.
        }

        f();
    }
}