promisify

Convert node.js style function into function that returns promise.

Usage

$ npm i --save @atsushi_suzuki/promisify

import * as fs from "fs";
import * as p from "@atsushi_suzuki/promisify";

(async function () {
  const readFile = p.fn(fs.readFile);
  const data = await readFile("package.json", "utf-8");

  console.log(data);
})();

API

function promisify(f: Function): (...args: any[]) => Promise

promisify node.js style function with single result.

usage:

const data = await p.promisify(fs.readFile)("package.json", "utf-8");

function promisifyn(f: Function): (...args: any[]) => Promise<any[]>

promisify node.js style function with multiple results.

usage:

const [bytesRead, buffer] = await p.promisifyn(fs.read)(fd, buf, offset, length, pos);

function call(f: Function, ...args: any[]): Promise

call node.js style function with single result.

usage:

const data = await p.call(fs.readFile, "package.json", "utf-8");

function calln(f: Function, ...args: any[]): Promise<any[]>

call node.js style function with multiple results.

usage:

const [bytesRead, buffer] = await p.calln(fs.read, fd, buf, offset, length, pos);

function wait(ee: EventEmitter, event: string): Promise

returns a promise to wait until specified event fires. with single event argument.

usage:

const data = await p.wait(rs, "data");

function waitn(ee: EventEmitter, event: string): Promise<any[]>

returns a promise to wait until specified event fires. with multiple event arguments.

usage:

const [code, signal] = await p.waitn(proc, "exit");

function waitAny(...defs: EventDefinition[]): Promise

returns a promise to wait until any of specified events fire.

type EventDefinition = [
  EventEmitter,
  {[event: string]: Function}
];

usage:

const data = await p.waitAny([conn, {
  "data": (data) => data,
  "close": () => Promise.reject(new Error("unexpected close")),
  "error": (err) => Promise.reject(err),
}]);