Dynamic Chaining in Javascript Promises

Question

How can I perform dynamic chaining in Javascript Promises, all the time I have seen only hardcoding of the calls for eg., (promise).then(request/funct

Answer 1

This is ES7 way.

Let's say you have multiple promises defined in an array.

  var funcs = [
    _ => new Promise(res => setTimeout(_ => res("1"), 1000)),
    _ => new Promise(res => setTimeout(_ => res("2"), 1000))
  }

And you want to call like this.

 chainPromises(funcs).then(result => console.log(result));

You can use async and await for this purpose.

  async function chainPromises(promises) {
    for (let promise of promises) {  // must be for (.. of ..)
      await promise();
    }
  }

This will execute the given functions sequentially(one by one), not in parallel. The parameter promises is an array of functions, which return Promise.

Plunker: http://plnkr.co/edit/UP0rhD?p=preview