Read or write-only private fields should be accessed properly

INVALID_PRIVATE_FIELD_ACCESS
Error
High
es13

This rule applies when read or write-only private fields of a class are not accessed properly.

TypeError exceptions are thrown in the following improper access cases:

A value is assigned to a private field declared as a getter without a corresponding setter.
A value is read from a private field declared as a setter without a corresponding getter.
A private method is updated to another value. Unlike public methods, private methods are not writable. You should use a private field with a function expression instead in this case.

-Noncompliant Code Example
+Compliant Code Example
 class Example {
   #firstName;
   #lastName;
   get #fullName() {
     return `${this.#firstName} ${this.#lastName}`;
   }
-  set #name(x) {
+  set #fullName(x) {
     const nameParts = x.split(/\s+/);
     this.#firstName = nameParts[0] || '';
     this.#lastName = nameParts[1] || '';
   }
-  #isValidName() {
+  #isValidName = () => this.#firstName !== '' && this.#lastName !== '';
     return this.#firstName !== '' && this.#lastName !== '';
   }
   constructor(fullName) {
-    this.#fullName = fullName || ''; // INVALID_PRIVATE_FIELD_ACCESS alarm because only getter is defined for '#fullName'.
+    this.#fullName = fullName || '';
     if (!this.#isValidName()) {
-      console.log(`${this.#name} is invalid!`); // INVALID_PRIVATE_FIELD_ACCESS alarm because only setter is defined for '#name'.
+      console.log(`${this.#fullName} is invalid!`);
     }
-    this.#isValidName = this.#isValidName.bind(this); // INVALID_PRIVATE_FIELD_ACCESS alarm because private method is read-only.
   }
 }

Noncompliant Code Example

View with compliant examples side by side

class Example {
  #firstName;
  #lastName;

  get #fullName() {
    return `${this.#firstName} ${this.#lastName}`;
  }
  set #name(x) {
    const nameParts = x.split(/\s+/);
    this.#firstName = nameParts[0] || '';
    this.#lastName = nameParts[1] || '';
  }
  #isValidName() {
    return this.#firstName !== '' && this.#lastName !== '';
  }

  constructor(fullName) {
    this.#fullName = fullName || ''; // INVALID_PRIVATE_FIELD_ACCESS alarm because only getter is defined for '#fullName'.
    if (!this.#isValidName()) {
      console.log(`${this.#name} is invalid!`); // INVALID_PRIVATE_FIELD_ACCESS alarm because only setter is defined for '#name'.
    }
    this.#isValidName = this.#isValidName.bind(this); // INVALID_PRIVATE_FIELD_ACCESS alarm because private method is read-only.
  }
}

Compliant Code Example

View with noncompliant examples side by side

class Example {
  #firstName;
  #lastName;

  get #fullName() {
    return `${this.#firstName} ${this.#lastName}`;
  }
  set #fullName(x) {
    const nameParts = x.split(/\s+/);
    this.#firstName = nameParts[0] || '';
    this.#lastName = nameParts[1] || '';
  }
  #isValidName = () => this.#firstName !== '' && this.#lastName !== '';

  constructor(fullName) {
    this.#fullName = fullName || '';
    if (!this.#isValidName()) {
      console.log(`${this.#fullName} is invalid!`);
    }
  }
}

Read or write-only private fields should be accessed properly

Noncompliant Code Example

Compliant Code Example

Version

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