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promisify

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 ...rest operator to pass in all the parameters.

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