Understand how promise work and execute in javascript

Promise.js

app.run(function ($http, $q) {
  var promise = $q.when('i m resolved');
   promise.then(function(value){
      console.log(value + " 1");
   });
   var innerPromise = promise.then(function(value){
      console.log(value + " 2");
   })
   var innerPromise2 = promise.then(function(value){
      console.log(value + " 3");
   })
   
   innerPromise2.then(function(){
     console.log('inner promise 2 first register then called');
   });
   innerPromise2.then(function(){
     console.log('inner promise 2 second register then called');
   });
   
   innerPromise.then(function(){
     console.log('inner promise 1 first register then called');
   });
   innerPromise.then(function(){
     console.log('inner promise 1 second register then called');
   });
  Promise.resolve()
  .then( () => {
    // Makes .then() return a rejected promise
    throw 'Oh no!';
  })
  .catch( reason => {
    console.error( 'onRejected function called: ', reason );
  })
  .then( () => {
    console.log("I am always called even if the prior then's promise rejects");
  });
  
})