constructor-super.md

title	rule_type	handled_by_typescript
constructor-super	problem	true

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.

This is a syntax error because there is no extends clause in the class:

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

Examples of incorrect code for this rule:

:::incorrect

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

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

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

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

:::

Examples of correct code for this rule:

:::correct

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

class A {
    constructor() { }
}

class B extends C {
    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.