Async method - promise.js

index.js

const fs = require('fs');
const Promise = require('promise');
const assert = require('assert');

/*
var p1 = new Promise(function(reject, resolve){

  //let result=  fs.readFileSync('./index.html');
  let result=  fs.readFileSync('./main.html');
  
  if(result)
        resolve(result);
  else
        reject("error");

});

p1.then(function(data){

    console.log("p1 resolved");

}, function(err){

    console.log(err);
});*/

var p3 = Promise.reject("manual reject");  //return a rejected promise 
var p4 = Promise.resolve("manual resolve");

p3.then((data)=>console.log(data), (err)=>console.log(err));

var read = Promise.denodeify(fs.readFile);

var fl = ['./main.html', './index.html'];

fl.forEach(function(index,i){

    read(index).then(function(data){

    //    console.log(data.toString());

       console.log("denodeify demo");
    })


});


Promise.all([Promise.resolve('a'), Promise.reject('b'), Promise.resolve('c')])
  .then(function (res) {
      console.log(res);
    assert.strictEqual(res[0], 'e');
    assert(res[1] === 'b');
    assert(res[2] === 'c');
    assert(false);
  });
// Promise() doesn't work with async function with callback unless we denodeify them.

/*
var p2 = new Promise(function(reject, resolve){


    fl.forEach(function(index, i){

        let result = fs.readFile(index, (err, data)=>{

            if(err)
                reject(err);
            else
            {
             console.log(i);
             if(i==(fl.length-1))
                resolve("async read completed");
            }
             
        });



    });
});


p2.then(function(data){

    console.log("p2 resolved");

}, function(err){

    console.log(err);
});
*/