Async traversal

Import as import * as t from 'neotraverse'.

forEachAsync · mapAsync

The callback may be async and is awaited at each node. Pass signal in options to cancel via AbortController.

t.mapAsync always runs immutably (like t.map).

Example: async transform

import * as t from 'neotraverse';

const doc = { title: 'Hello', body: 'world' };

const translated = await t.mapAsync(doc, async (ctx, x) => {
  if (typeof x === 'string') ctx.update(await translate(x));
});

Example: abort

import * as t from 'neotraverse';

const controller = new AbortController();
const walking = t.forEachAsync(
  big,
  async (ctx) => {
    /* … */
  },
  { signal: controller.signal }
);
controller.abort(); // → `walking` rejects with the abort reason

Concurrency

forEachAsync / mapAsync accept { concurrency: n } (default 1) to run up to n sibling callbacks in parallel. Each branch gets an isolated path/parent snapshot, intended for I/O-bound work; pair with signal to abort.

Example

import * as t from 'neotraverse';

const obj = { a: 0, b: 0, c: 0 };

await t.forEachAsync(
  obj,
  async (ctx) => {
    await fetch(`/api/item/${ctx.key}`);
  },
  { concurrency: 3 }
);
// up to three sibling fetches in flight at once