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

Answer 1

You should use arrow function here, to preserve existense of this.

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

In doing so, this inside of the function is bound to the outer context. It is the same as:

setTimeout(function(){
    this.http.post();
}.bind(this));