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noDuplicateClassMembers (since v1.0.0)

Diagnostic Category: lint/suspicious/noDuplicateClassMembers

Source: no-dupe-class-members

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

Section titled Examples

Invalid

Section titled Invalid
class Foo {
  bar() { }
  bar() { }
}
suspicious/noDuplicateClassMembers.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━

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

class Foo {
  bar() { }
  get bar() { }
}
suspicious/noDuplicateClassMembers.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━

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

class Foo {
  bar;
  bar() { }
}
suspicious/noDuplicateClassMembers.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━

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

class Foo {
  static bar() { }
  static bar() { }
}
suspicious/noDuplicateClassMembers.js:3:3 lint/suspicious/noDuplicateClassMembers ━━━━━━━━━━━━━━━━━━

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

Valid

Section titled Valid
class Foo {
  bar() { }
  qux() { }
}
class Foo {
  set bar(value) { }
  get bar() { }
}
class Foo {
  bar;
  qux;
}
class Foo {
  bar;
  qux() { }
}
class Foo {
  static bar() { }
  bar() { }
}
Section titled Related links