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TS JS Deno

Converts an asynchronous function to return a promise.

In Node 8+, you can use util.promisify

Use currying to return a function returning a Promise that calls the original function. Use the operator to pass in all the parameters.

const promisify =
(func: Function) =>
(...args: any[]) =>
new Promise((resolve, reject) =>
func(...args, (err: Error, result: any) =>
err ? reject(err) : resolve(result)
const delay = promisify((d, cb) => setTimeout(cb, d));
delay(2000).then(() => console.log("Hi!")); // // Promise resolves after 2s