Verify calls of super() in constructors (constructor-super)

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

Constructors of derived classes must call super(). Constructors of non derived classes must not call super(). If this is not observed, the JavaScript engine will raise a runtime error.

This rule checks whether or not there is a valid super() call.

Rule Details

This rule is aimed to flag invalid/missing super() calls.

Examples of incorrect code for this rule:

/*eslint constructor-super: "error"*/
/*eslint-env es6*/

class A {
    constructor() {
        super();  // This is a SyntaxError.
    }
}

class A extends B {
    constructor() { }  // Would throw a ReferenceError.
}

// Classes which inherits from a non constructor are always problems.
class A extends null {
    constructor() {
        super();  // Would throw a TypeError.
    }
}

class A extends null {
    constructor() { }  // Would throw a ReferenceError.
}

Examples of correct code for this rule:

/*eslint constructor-super: "error"*/
/*eslint-env es6*/

class A {
    constructor() { }
}

class A extends B {
    constructor() {
        super();
    }
}

When Not To Use It

If you don’t want to be notified about invalid/missing super() callings in constructors, you can safely disable this rule.

Version

This rule was introduced in ESLint 0.24.0.

Resources

• Rule source
• Documentation source