noUnusedPrivateClassMembers

Diagnostic Category: lint/correctness/noUnusedPrivateClassMembers

JavaScript (and super languages)

Since: v1.3.3

Sources:

Same as: no-unused-private-class-members

Description

Disallow unused private class members

Private class members that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such class members take up space in the code and can lead to confusion by readers.

Examples

Invalid

class OnlyWrite {
  #usedOnlyInWrite = 5;

  method() {
       this.#usedOnlyInWrite = 212;
  }
}

code-block.js:2:3 lint/correctness/noUnusedPrivateClassMembers  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This private class member is defined but never used.
  
    1 │ class OnlyWrite {
  > 2 │   #usedOnlyInWrite = 5;
      │   ^^^^^^^^^^^^^^^^
    3 │ 
    4 │   method() {
  
  ℹ Unsafe fix: Remove unused declaration.
  
    1 1 │   class OnlyWrite {
    2   │ - ··#usedOnlyInWrite·=·5;
    3 2 │   
    4 3 │     method() {

 class TsBioo {
   private unusedProperty = 5;
 }

code-block.ts:2:12 lint/correctness/noUnusedPrivateClassMembers  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This private class member is defined but never used.
  
    1 │  class TsBioo {
  > 2 │    private unusedProperty = 5;
      │            ^^^^^^^^^^^^^^
    3 │  }
    4 │ 
  
  ℹ Unsafe fix: Remove unused declaration.
  
    1 1 │    class TsBioo {
    2   │ - ···private·unusedProperty·=·5;
    3 2 │    }
    4 3 │

 class TsBioo {
   private unusedMethod() {}
 }

code-block.ts:2:12 lint/correctness/noUnusedPrivateClassMembers  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━

  ⚠ This private class member is defined but never used.
  
    1 │  class TsBioo {
  > 2 │    private unusedMethod() {}
      │            ^^^^^^^^^^^^
    3 │  }
    4 │ 
  
  ℹ Unsafe fix: Remove unused declaration.
  
    1 1 │    class TsBioo {
    2   │ - ···private·unusedMethod()·{}
    3 2 │    }
    4 3 │

Valid

class UsedMember {
  #usedMember = 42;

  method() {
       return this.#usedMember;
  }
}

How to configure

{
  "linter": {
    "rules": {
      "correctness": {
        "noUnusedPrivateClassMembers": "error"
      }
    }
  }
}