accessor-pairs

A property with a setter and no getter can be written but never read. user.name = "Ada" works, but user.name is undefined. Most of the time, someone forgot the getter.

The rule looks at object literals, classes, and the descriptors passed to Object.defineProperty(), Object.defineProperties(), Object.create() and Reflect.defineProperty(). A getter without a setter is a read-only property, so it's allowed by default.

Configure

Off by default. To turn it on:

[lint.rules]
"accessor-pairs" = "error" # or "warn"

Every option, set to its default:

[lint.rules]
"accessor-pairs" = ["error", {
  setWithoutGet = true,
  getWithoutSet = false,
  enforceForClassMembers = true,
  enforceForTSTypes = false,
}]

Examples

Reported:

const user = {
  set name(value) {
    this._name = value.trim();
  },
};

Object.defineProperty(user, "name", {
  set(value) {
    this._name = value.trim();
  },
});

Not reported:

const user = {
  get name() {
    return this._name;
  },
  set name(value) {
    this._name = value.trim();
  },
};

const config = {
  get version() {
    return 3;
  },
};

Options

Option	Default	What it does
setWithoutGet	true	Report a setter that has no getter.
getWithoutSet	false	Report a getter that has no setter.
enforceForClassMembers	true	Also check classes. A static accessor only pairs with a static one.
enforceForTSTypes	false	Also check TypeScript interfaces and object types.

const config = {
  get version() {
    return 3;
  },
};

class User {
  set name(value) {
    this._name = value.trim();
  }
}

interface User {
  set name(value: string);
}