effector/no-duplicate-clock-or-source-array-values

This rule forbids duplicate units in the array form of clock or source for sample and guard.

Duplicate units in a clock array do not change runtime behavior and thus are almost always a mistake. This typically occurs due to copy-paste errors or during refactoring when dealing with many units with similar names.

While duplicates in a source array do affect runtime behavior, this is still usually unintentional. This rule helps catch these errors automatically, making debugging easier and keeping your code clean.

import { sample, createEvent, createStore } from "effector"

const event = createEvent()
const other = createEvent()
const $store = createStore("value")

sample({
  // 👎 duplicated `event` in the clock array is redundant and likely a mistake
  clock: [
    event,
    other,
    event, 
  ],
  source: $store,
  fn: (x) => x * 2,
  target: $store,
})

sample({
  // 👍 each unit in the clock array is unique, making the intent clear
  clock: [event, other], 
  source: $store,
  fn: (x) => x * 2,
  target: $store,
})