Mixing
mergeMap an Observable with array value
I want to map the values of an array from an Observable with additional data.
For example: I have a team (of users) and the values I receive from the service contains an array of users. But before I assign this list to a local variable I would like to add additional data to the User objects (let's say the amount of goals a User has made).
public team: Array<User> = ;
this.userService.getCurrentTeam()
// the result is an array of users: [{id: 1, name: 'John'}, {id: 6, name: 'Jane'}, ...]
.mergeMap(people => people) // flatten the array
.mergeMap(person => {
return this.gameService.getGoalsForUser(person);
}).subscribe((team) => {
this.people = team; // this won't work: see below
});
As the result of getCurrentTeam() is an array of Users I first need to break up (flatten) this array (done with the first mergeMap) to be able to get the goals for every user in the mergeMap function.
To make the above block work the subscribe function needs to be rewritten as the team variable is not an array anymore:
subscribe((person) => { this.team.push(person); } );
The problem with this subscription is that whenever the data changes, a duplicate user can be pushed into the team array.
I have two questions regarding this concept:
- How can I make the additional requests for the individual users without breaking up the array (in the first mergeMap function)
- Can I keep my array in the subscribe function? (
this.people = team;)
arrays angularjs typescript ionic-framework observable
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
add a comment |
I want to map the values of an array from an Observable with additional data.
For example: I have a team (of users) and the values I receive from the service contains an array of users. But before I assign this list to a local variable I would like to add additional data to the User objects (let's say the amount of goals a User has made).
public team: Array<User> = ;
this.userService.getCurrentTeam()
// the result is an array of users: [{id: 1, name: 'John'}, {id: 6, name: 'Jane'}, ...]
.mergeMap(people => people) // flatten the array
.mergeMap(person => {
return this.gameService.getGoalsForUser(person);
}).subscribe((team) => {
this.people = team; // this won't work: see below
});
As the result of getCurrentTeam() is an array of Users I first need to break up (flatten) this array (done with the first mergeMap) to be able to get the goals for every user in the mergeMap function.
To make the above block work the subscribe function needs to be rewritten as the team variable is not an array anymore:
subscribe((person) => { this.team.push(person); } );
The problem with this subscription is that whenever the data changes, a duplicate user can be pushed into the team array.
I have two questions regarding this concept:
- How can I make the additional requests for the individual users without breaking up the array (in the first mergeMap function)
- Can I keep my array in the subscribe function? (
this.people = team;)
arrays angularjs typescript ionic-framework observable
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
add a comment |
I want to map the values of an array from an Observable with additional data.
For example: I have a team (of users) and the values I receive from the service contains an array of users. But before I assign this list to a local variable I would like to add additional data to the User objects (let's say the amount of goals a User has made).
public team: Array<User> = ;
this.userService.getCurrentTeam()
// the result is an array of users: [{id: 1, name: 'John'}, {id: 6, name: 'Jane'}, ...]
.mergeMap(people => people) // flatten the array
.mergeMap(person => {
return this.gameService.getGoalsForUser(person);
}).subscribe((team) => {
this.people = team; // this won't work: see below
});
As the result of getCurrentTeam() is an array of Users I first need to break up (flatten) this array (done with the first mergeMap) to be able to get the goals for every user in the mergeMap function.
To make the above block work the subscribe function needs to be rewritten as the team variable is not an array anymore:
subscribe((person) => { this.team.push(person); } );
The problem with this subscription is that whenever the data changes, a duplicate user can be pushed into the team array.
I have two questions regarding this concept:
- How can I make the additional requests for the individual users without breaking up the array (in the first mergeMap function)
- Can I keep my array in the subscribe function? (
this.people = team;)
arrays angularjs typescript ionic-framework observable
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
I want to map the values of an array from an Observable with additional data.
For example: I have a team (of users) and the values I receive from the service contains an array of users. But before I assign this list to a local variable I would like to add additional data to the User objects (let's say the amount of goals a User has made).
public team: Array<User> = ;
this.userService.getCurrentTeam()
// the result is an array of users: [{id: 1, name: 'John'}, {id: 6, name: 'Jane'}, ...]
.mergeMap(people => people) // flatten the array
.mergeMap(person => {
return this.gameService.getGoalsForUser(person);
}).subscribe((team) => {
this.people = team; // this won't work: see below
});
As the result of getCurrentTeam() is an array of Users I first need to break up (flatten) this array (done with the first mergeMap) to be able to get the goals for every user in the mergeMap function.
To make the above block work the subscribe function needs to be rewritten as the team variable is not an array anymore:
subscribe((person) => { this.team.push(person); } );
The problem with this subscription is that whenever the data changes, a duplicate user can be pushed into the team array.
I have two questions regarding this concept:
- How can I make the additional requests for the individual users without breaking up the array (in the first mergeMap function)
- Can I keep my array in the subscribe function? (
this.people = team;)
arrays angularjs typescript ionic-framework observable
arrays angularjs typescript ionic-framework observable
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
asked Jan 2 at 18:50
Hans VnHans Vn
5741131
5741131
add a comment |
add a comment |
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