Disallow modifying variables of class declarations (no-class-assign)

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

ClassDeclaration creates a variable, and we can modify the variable.

/*eslint-env es6*/

class A { }
A = 0;

But the modification is a mistake in most cases.

Rule Details

This rule is aimed to flag modifying variables of class declarations.

Examples of incorrect code for this rule:

/*eslint no-class-assign: "error"*/
/*eslint-env es6*/

class A { }
A = 0;

/*eslint no-class-assign: "error"*/
/*eslint-env es6*/

A = 0;
class A { }

/*eslint no-class-assign: "error"*/
/*eslint-env es6*/

class A {
    b() {
        A = 0;
    }
}

/*eslint no-class-assign: "error"*/
/*eslint-env es6*/

let A = class A {
    b() {
        A = 0;
        // `let A` is shadowed by the class name.
    }
}

Examples of correct code for this rule:

/*eslint no-class-assign: "error"*/
/*eslint-env es6*/

let A = class A { }
A = 0; // A is a variable.

/*eslint no-class-assign: "error"*/
/*eslint-env es6*/

let A = class {
    b() {
        A = 0; // A is a variable.
    }
}

/*eslint no-class-assign: 2*/
/*eslint-env es6*/

class A {
    b(A) {
        A = 0; // A is a parameter.
    }
}

When Not To Use It

If you don’t want to be notified about modifying variables of class declarations, you can safely disable this rule.

Version

This rule was introduced in ESLint 1.0.0-rc-1.

Resources

• Rule source
• Documentation source