How can i use promises to get the value

Question

I have tried this but gives me a promise I just want do it like this.

function doSome() {
  return new Promise(
    function(res, rej) {
      let d = [];
      for (var i = 0; i < 100; i++) {
        d.push(i)
      }
      res(d)
    })

}
console.log(doSome().then((val)=>{return val}));

Answer 1

The provided code will not print the expected output because you're trying to console.log() the Promise itself rather than its value. Since console.log() issynchronous, while Promise has anasynchronousnature, the issue can be solved by moving the logging into then block:

function doSome() {
  return new Promise(
    function(res, rej) {
      let d = [];
      for (var i = 0; i < 100; i++) {
        d.push(i)
      }
      res(d)
    })

}

doSome()
  .then((val) => { return val })
  .then((val) => console.log(val));