In the constructor of derived classes, if this/super are used before super() calls, it raises a reference error.

This rule checks this/super keywords in constructors, then reports those that are before super().

Rule Details

This rule is aimed to flag this/super keywords before super() callings.

Examples

Examples of incorrect code for this rule:

::: incorrect

/*eslint no-this-before-super: "error"*/

class A1 extends B {
    constructor() {
        this.a = 0;
        super();
    }
}

class A2 extends B {
    constructor() {
        this.foo();
        super();
    }
}

class A3 extends B {
    constructor() {
        super.foo();
        super();
    }
}

class A4 extends B {
    constructor() {
        super(this.foo());
    }
}

:::

Examples of correct code for this rule:

::: correct

/*eslint no-this-before-super: "error"*/

class A1 {
    constructor() {
        this.a = 0; // OK, this class doesn't have an `extends` clause.
    }
}

class A2 extends B {
    constructor() {
        super();
        this.a = 0; // OK, this is after `super()`.
    }
}

class A3 extends B {
    foo() {
        this.a = 0; // OK. this is not in a constructor.
    }
}

:::

When Not To Use It

If you don't want to be notified about using this/super before super() in constructors, you can safely disable this rule.