How to 'wait' for two observables in RxJS

Question

In my app i have something like:

this._personService.getName(id)
      .concat(this._documentService.getDocument())
      .subscribe((response) => {
              


        

Answer 1

You can use 'zip' or 'buffer' like the following.

function getName() {
    return Observable.of('some name').delay(100);
}

function getDocument() {
    return Observable.of('some document').delay(200);
}

// CASE1 : concurrent requests
Observable.zip(getName(), getDocument(), (name, document) => {
    return `${name}-${document}`;
})
    .subscribe(value => console.log(`concurrent: ${value}`));

// CASE2 : sequential requests
getName().concat(getDocument())
    .bufferCount(2)
    .map(values => `${values[0]}-${values[1]}`)
    .subscribe(value => console.log(`sequential: ${value}`));