no-setter-return

Disallow returning values from setters

Setters cannot return values.

While returning a value from a setter does not produce an error, the returned value is being ignored. Therefore, returning a value from a setter is either unnecessary or a possible error, since the returned value cannot be used.

Rule Details

This rule disallows returning values from setters and reports return statements in setter functions.

Only return without a value is allowed, as it’s a control flow statement.

This rule checks setters in:

• Object literals.
• Class declarations and class expressions.
• Property descriptors in Object.create, Object.defineProperty, Object.defineProperties, and Reflect.defineProperty methods of the global objects.

Examples of incorrect code for this rule:

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

var foo = {
    set a(value) {
        this.val = value;
        return value;
    }
};

class Foo {
    set a(value) {
        this.val = value * 2;
        return this.val;
    }
}

const Bar = class {
    static set a(value) {
        if (value < 0) {
            this.val = 0;
            return 0;
        }
        this.val = value;
    }
};

Object.defineProperty(foo, "bar", {
    set(value) {
        if (value < 0) {
            return false;
        }
        this.val = value;
    }
});
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Examples of correct code for this rule:

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

var foo = {
    set a(value) {
        this.val = value;
    }
};

class Foo {
    set a(value) {
        this.val = value * 2;
    }
}

const Bar = class {
    static set a(value) {
        if (value < 0) {
            this.val = 0;
            return;
        }
        this.val = value;
    }
};

Object.defineProperty(foo, "bar", {
    set(value) {
        if (value < 0) {
            throw new Error("Negative value.");
        }
        this.val = value;
    }
});
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Handled by TypeScript

It is safe to disable this rule when using TypeScript because TypeScript's compiler enforces this check.

Related Rules

• getter-return

Version

This rule was introduced in ESLint v6.7.0.

Further Reading

setter - JavaScript | MDN
developer.mozilla.org

Resources

• Rule source
• Tests source