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no-writeonly

Disallow setter-only accessors.

Targeted pattern scope​

This rule targets object and class accessors.

What this rule reports​

This rule reports setters that do not have corresponding getters.

Why this rule exists​

Write-only properties hide state flow and make object behavior harder to debug.

❌ Incorrect​

const state = {
 set value(next: number) {
  this._value = next;
 },
};

✅ Correct​

const state = {
 _value: 0,
 get value() {
  return this._value;
 },
 set value(next: number) {
  this._value = next;
 },
};

Behavior and migration notes​

This rule forwards options and behavior to ESLint core accessor-pairs.

Additional examples​

class Box {
 set value(next: number) {
  this._value = next;
 }
}
// ❌ reported

class BoxFixed {
 _value = 0;

 get value() {
  return this._value;
 }

 set value(next: number) {
  this._value = next;
 }
}
// ✅ valid

ESLint flat config example​

import etcMisc from "eslint-plugin-etc-misc";

export default [
 {
  plugins: { "etc-misc": etcMisc },
  rules: {
   "etc-misc/no-writeonly": "error",
  },
 },
];

When not to use it​

Disable this rule if you intentionally use write-only sink objects and the pattern is documented.

Package documentation​

Rule catalog ID: R052

Further reading​

Adoption resources​

  • Start at warning level in CI, then move to error after cleanup.
  • Use focused codemods/autofix batches per package or directory.