runOnRuntimeAsync

Available from 0.8.0

runOnRuntimeAsync lets you asynchronously run worklet functions on a Worker Runtime. It returns a Promise of the worklet function's return value. The Promise is resolved asynchronously, not immediately after the callback execution.

Reference

Code

Code

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1function sum(numbers) {

2 'worklet';

3 return numbers.reduce((total, n) => total + n, 0);

4}

5

6const workletRuntime = createWorkletRuntime({ name: 'background' });

7const data = [1, 2, 3, 4];

8const pending = runOnRuntimeAsync(workletRuntime, sum, data);

9console.log('The RN Runtime continues while the worker computes');

10const result = await pending;

11console.log('Computation result:', result); // 10

Type definitions

function runOnRuntimeAsync<Args extends unknown[], ReturnValue>(
  workletRuntime: WorkletRuntime,
  worklet: (...args: Args) => ReturnValue,
  ...args: Args
): Promise<ReturnValue>;

Arguments

workletRuntime

The worklet runtime to run the worklet function on. Created with createWorkletRuntime.

worklet

A reference to a function you want to execute on the Worker Runtime. Arguments to your function have to be passed after the worklet function i.e. runOnRuntimeAsync(workletRuntime, setValue, 10);.

args

Arguments to the function you want to execute on the Worker Runtime.

Remarks

• It's a common mistake to execute function inside of runOnRuntimeAsync like this: runOnRuntimeAsync(workletRuntime, myWorklet(10)). Here, the correct usage would be runOnRuntimeAsync(workletRuntime, myWorklet, 10).

• The callback passed as the argument is automatically workletized and ready to be run on the Worker Runtime.

• Errors thrown in the worklet function will cause the Promise to reject with that error.

Call table

Mode	RN Runtime	UI Runtime	Worker Runtime
Bundle Mode	✅	✅	✅
Legacy Eval Mode	✅	❌	❌

What does it mean?

Platform compatibility

Native	Web
✅	❌