Callback - API reference

API reference › @evolu/common › Types › Callback

type Callback<T> = (value: T) => void;

Defined in: packages/common/src/Types.ts:37

A function that receives a value and returns nothing.

Use for event handlers, observers, and async completion handlers.

Completion callbacks

import { assertEqual, ok, type Callback, type Result } from "@evolu/common";

const completedValues: Array<string> = [];
const onComplete: Callback<string> = (value) => {
  completedValues.push(value);
};
const queue = new Set<Callback<Result<string, Error>>>();
queue.add((result) => {
  if (result.ok) completedValues.push(result.value);
});

onComplete("direct");
for (const callback of queue) callback(ok("queued"));

assertEqual(completedValues, ["direct", "queued"]);