The of() operator essentially converted a list of arguments to an Observable. Since arrays are often how we structure list of things in JavaScript, we should have a way of transforming arrays into Observables. This lesson teaches how you can convert from Arrays to Observables, from Promises to Observables, and from Iterators to Observables.
formArray:
var ary = [,,];
var foo = Rx.Observable.fromArray(ary); foo.subscribe(function (x) {
console.log('next ' + x);
}, function (err) {
console.log('error ' + err);
}, function () {
console.log('done');
}); /*
"next 1"
"next 2"
"next 3"
"done"
*/
fromPromise:
var prom = fetch('https://null.jsbin.com');
var foo = Rx.Observable.fromPromise(prom);
foo.subscribe(function (x) {
console.log('next ' + x.status);
}, function (err) {
console.log('error ' + err);
}, function () {
console.log('done');
});
/*
"next 204"
"done"
*/
from:
from() opreator can create observalbes according to what you passed in
=fromArray:
var ary = [,,];
var foo = Rx.Observable.from(ary); foo.subscribe(function (x) {
console.log('next ' + x);
}, function (err) {
console.log('error ' + err);
}, function () {
console.log('done');
}); /*
"next 1"
"next 2"
"next 3"
"done"
*/
=fromPromiose
var foo = Rx.Observable.from(prom);
foo.subscribe(function (x) {
console.log('next ' + x.status);
}, function (err) {
console.log('error ' + err);
}, function () {
console.log('done');
});
From iterator:
function* generator(){
yield ;
yield ;
yield ;
}
var iterator = generator();
var foo = Rx.Observable.from(iterator);
foo.subscribe(function (x) {
console.log('next ' + x);
}, function (err) {
console.log('error ' + err);
}, function () {
console.log('done');
});
/*
"next 10"
"next 20"
"next 30"
"done"
*/