Disallow to use this/super before super() calling in constructors. (no-this-before-super)

On the constructor of derived classes, if this/super are used before super(), 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.

The following patterns are considered warnings:

class A extends B {
    constructor() {
        this.a = 0; // this is before `super()`.
        super();
    }
}

class A extends B {
    constructor() {
        this.foo(); // this is before `super()`.
        super();
    }
}

class A extends B {
    constructor() {
        super.foo(); // this is before `super()`.
        super();
    }
}

class A extends B {
    constructor() {
        super(this.foo()); // `super()` is not called yet.
    }
}

The following patterns are not considered warnings:

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

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

class A 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.

Version

This rule was introduced in ESLint 0.24.0.

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