easy-currencies/src/parts/utils.ts

A tool for easy conversion of currencies.

import { UserDefinedProvider, Provider } from "./providers";

/**
 * Utility for typechecking UserDefinedProvider objects
 *
 * @export
 * @param {(UserDefinedProvider | any)} userDefinedProvider - The UserDefinedProvider object to be checked
 * @returns {u is UserDefinedProvider}
 */
export function checkIfUserDefinedProvider(
  userDefinedProvider: UserDefinedProvider | any
): userDefinedProvider is UserDefinedProvider {
  return (
    (userDefinedProvider as UserDefinedProvider).name !== undefined &&
    checkIfProvider((userDefinedProvider as UserDefinedProvider).provider)
  );
}

/**
 * Utility for typechecking Provider objects
 *
 * @export
 * @param {(Provider | any)} provider - The Provider object to be checked
 * @returns {p is Provider}
 */
export function checkIfProvider(
  provider: Provider | any
): provider is Provider {
  return (
    (provider as Provider).endpoint !== undefined &&
    (provider as Provider).errorHandler !== undefined &&
    (provider as Provider).errors !== undefined &&
    (provider as Provider).handler !== undefined &&
    (provider as Provider).key !== undefined
  );
}


/**
 * Wraps a promise and handles both the resolved value and any potential errors.
 * @param promise - The promise to wrap.
 * @returns A promise that resolves to a tuple containing the error (if any) and the resolved value (if any).
 */
export function _to<T, U = Error>(
  promise: Promise<T>,
): Promise<[U | null, T | null]> {
  return promise
    .then((data: T): [null, T] => [null, data])
    .catch((err: U): [U, null] => [err, null]);
}


/**
 * Delays execution by the specified amount of time.
 *
 * @param ms - The number of milliseconds to wait.
 * @returns A promise that resolves after the specified delay.
 */
export function sleep(ms: number): Promise<void> {
  return new Promise(resolve => setTimeout(resolve, ms));
}