noDuplicateClassMembers

JavaScript (and super languages)

Summary

Rule available since: v1.0.0
Diagnostic Category: lint/suspicious/noDuplicateClassMembers
This rule is recommended, which means is enabled by default.
This rule doesn’t have a fix.
The default severity of this rule is error.
Sources:
- Same as no-dupe-class-members
- Same as @typescript-eslint/no-dupe-class-members

Description

Disallow duplicate class members.

If there are declarations of the same name among class members, the last declaration overwrites other declarations silently. It can cause unexpected behaviours.

Examples

Invalid

1
class Foo {
2
  bar() { }
3
  bar() { }
4
}

code-block.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Duplicate class member name “bar”
  
    1 │ class Foo {
    2 │   bar() { }
  > 3 │   bar() { }
      │   ^^^^^^^^^
    4 │ }
    5 │

1
class Foo {
2
  bar() { }
3
  get bar() { }
4
}

code-block.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Duplicate class member name “bar”
  
    1 │ class Foo {
    2 │   bar() { }
  > 3 │   get bar() { }
      │   ^^^^^^^^^^^^^
    4 │ }
    5 │

1
class Foo {
2
  bar;
3
  bar() { }
4
}

code-block.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Duplicate class member name “bar”
  
    1 │ class Foo {
    2 │   bar;
  > 3 │   bar() { }
      │   ^^^^^^^^^
    4 │ }
    5 │

1
class Foo {
2
  static bar() { }
3
  static bar() { }
4
}

code-block.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ Duplicate class member name “bar”
  
    1 │ class Foo {
    2 │   static bar() { }
  > 3 │   static bar() { }
      │   ^^^^^^^^^^^^^^^^
    4 │ }
    5 │

Valid

1
class Foo {
2
  bar() { }
3
  qux() { }
4
}

1
class Foo {
2
  set bar(value) { }
3
  get bar() { }
4
}

1
class Foo {
2
  bar;
3
  qux;
4
}

1
class Foo {
2
  bar;
3
  qux() { }
4
}

1
class Foo {
2
  static bar() { }
3
  bar() { }
4
}

How to configure

1
{
2
  "linter": {
3
    "rules": {
4
      "suspicious": {
5
        "noDuplicateClassMembers": "error"
6
      }
7
    }
8
  }
9
}

noDuplicateClassMembers

Summary

Description

Examples

Invalid

Valid

How to configure

Related links