Variable inside setTimeout says it is undefined, but when outside it is defined [duplicate]

Answer 1

it's not same this inside setTimeout when you use function(){...

2 most popular ways for this issue:

1) use extra variable to store outside "this"

var that = this;
this.http.post( ...//http variable is defined here
           setTimeout(function(){
               that.http.post(...  //http is not defined here
        }
   }

2) use arrow functions

this.http.post( ...//http variable is defined here
           setTimeout(() => {
               that.http.post(...  //http is not defined here
        }
   }

1st way is old ES5 and you don't need any compilers, for ES6 version (#2) you will need to use something like babel.

find more about arrow functions & babel here: https://babeljs.io/docs/learn-es2015/