no-class-assign

Disallow reassigning class members

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

class A { }
A = 0;
1
2

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"*/

class A { }
A = 0;
1
2
3
4

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

A = 0;
class A { }
1
2
3
4

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

class A {
    b() {
        A = 0;
    }
}
1
2
3
4
5
6
7

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

let A = class A {
    b() {
        A = 0;
        // `let A` is shadowed by the class name.
    }
}
1
2
3
4
5
6
7
8

Examples of correct code for this rule:

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

let A = class A { }
A = 0; // A is a variable.
1
2
3
4

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

let A = class {
    b() {
        A = 0; // A is a variable.
    }
}
1
2
3
4
5
6
7

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

class A {
    b(A) {
        A = 0; // A is a parameter.
    }
}
1
2
3
4
5
6
7

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.

Handled by TypeScript

It is safe to disable this rule when using TypeScript because TypeScript's compiler enforces this check.

Version

This rule was introduced in ESLint v1.0.0-rc-1.

Resources

• Rule source
• Tests source