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Disallow returning values from setters (no-setter-return)

The "extends": "eslint:recommended" property in a configuration file enables this rule.

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;
    }
});

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;
    }
});

Further Reading

Version

This rule was introduced in ESLint 6.7.0.

Resources

© JS Foundation and other contributors
Licensed under the MIT License.
https://eslint.org/docs/rules/no-setter-return