Declare a variable and store retrieve data inside - json

Question

I have managed to retrieve data from Firebase, however, I am unable to store the data into a variable I have declared. I want to store in a variable is so that I am able to use at another method.
Please help.
These are the codes that I have tried.
1st method, rest api
retrieveUser(){
this.restProvider.retrieveUser(this.emailAdd, this.pw)
.subscribe(listUser => {
this.users = userList.results //trying to store to users variable
console.log(listUser);
},
err => {
console.log(err);
},
() => console.log('success')
);}
2nd method to use for some IF-ELSE
loginBtnPress(event){
this.retrieveUser();
console.log(this.users);
}

Answer 1

You are doing it wrong. this.users is getting updated using observables. So, if you try to retrieve its value before the value has been updated, you wont get it as expected. You can call it as below,
retrieveUser(){
this.restProvider.retrieveUser(this.emailAdd, this.pw)
.subscribe(listUser => {
this.users = userList.results //trying to store to users variable
callYourMethodWithUpdatedValue(this.users); // <-- Pass value here
},
err => {
console.log(err);
},
() => console.log('success')
);}
The callYourMethodWithUpdatedValue is called every time(and as soon as) the value this.users is updated
Update 1
You can't retrieve async value in one method and expect that value to be used in some other method on button click. Reason being, your are expecting value on that button click , but since its a async call (can take n secs), you can't be assured that the value will be populated when the value is used through some button call.
That's wrong implementation. You need to change the architecture to either of below:
Don't route to that page unless the user value has been resolved (received). Check canActivate and canActivateChildren.
Change the UX where you are trying to retrieve the use async variable on button click, and activate the button when the value has been received (Here you can use Subject ). Something like this demo