Function createPromise

createPromise<S, E>(
    executor: (
        resolve: (value: S) => void,
        reject: (reason?: E) => void,
    ) => void,
): Promise<Result<S, E>>

Creates a Promise that wraps the result in a Result type for type-safe error handling. This function is an alternative to new Promise(executor) that provides enhanced type safety by returning a Result type instead of throwing exceptions.

Type Parameters

S
The type of successful value
E
The type of error value

Parameters

executor: (resolve: (value: S) => void, reject: (reason?: E) => void) => void
Function that takes resolve and reject callbacks

Returns Promise<Result<S, E>>

A Promise that resolves to a Result containing either success or error

Example

// Create a promise that resolves successfully
const successPromise = createPromise<number, string>((resolve) => {
  setTimeout(() => {
    resolve(42);
  }, 0);
});

const successResult = await successPromise;
assert.ok(Result.isOk(successResult));
if (Result.isOk(successResult)) {
  assert(successResult.value === 42);
}

// Create a promise that rejects with an error
const errorPromise = createPromise<number, string>((_, reject) => {
  setTimeout(() => {
    reject('Something went wrong');
  }, 0);
});

const errorResult = await errorPromise;
assert.ok(Result.isErr(errorResult));
if (Result.isErr(errorResult)) {
  assert(errorResult.value === 'Something went wrong');
}