typescript/prefer-readonly Nursery

💭 This rule requires type information.

Require class members that are never reassigned to be marked readonly.

Members that never change should be declared readonly to make class invariants explicit and prevent accidental mutation.

Examples of incorrect code for this rule:

class Counter {
  private value = 0;

  getValue() {
    return this.value;
  }
}

Examples of correct code for this rule:

class Counter {
  private readonly value = 0;

  getValue() {
    return this.value;
  }
}

Configuration

This rule accepts a configuration object with the following properties:

type: boolean

default: false

Restrict checks to members immediately initialized with inline lambda values.

To enable this rule using the config file or in the CLI, you can use:

Config (.oxlintrc.json)CLI

json

{
  "rules": {
    "typescript/prefer-readonly": "error"
  }
}

bash

oxlint --type-aware --deny typescript/prefer-readonly