How to correctly declare or require in reference to the rxjs library?

Question

Using nodejs and typescript to review another answer to a different question, I get this exception:

TypeError: interval$.zip is not a function

My code (rxjs2.ts):

{
    var Rx = require('rxjs');

    const interval$ = Rx.interval(1000);
    const items$ = Rx.from([1,2,3]);

    const itemsOverTime$ = interval$.zip(items$).repeat();

    itemsOverTime$.subscribe(([time, val]) => {
    console.log(val);
    // 1
    // 2
    // 3
    // 1
    // 2
    // 3
    });
}

Running this from VSCode console, like: node rxjs2.ts

My package-lock.json

{
  "requires": true,
  "lockfileVersion": 1,
  "dependencies": {
    "@types/node": {
      "version": "10.12.2",
      "resolved": "https://registry.npmjs.org/@types/node/-/node-10.12.2.tgz",
      "integrity": "sha512-53ElVDSnZeFUUFIYzI8WLQ25IhWzb6vbddNp8UHlXQyU0ET2RhV5zg0NfubzU7iNMh5bBXb0htCzfvrSVNgzaQ=="
    },
    "rxjs": {
      "version": "6.3.3",
      "resolved": "https://registry.npmjs.org/rxjs/-/rxjs-6.3.3.tgz",
      "integrity": "sha512-JTWmoY9tWCs7zvIk/CvRjhjGaOd+OVBM987mxFo+OW66cGpdKjZcpmc74ES1sB//7Kl/PAe8+wEakuhG4pcgOw==",
      "requires": {
        "tslib": "1.9.3"
      }
    },
    "tslib": {
      "version": "1.9.3",
      "resolved": "https://registry.npmjs.org/tslib/-/tslib-1.9.3.tgz",
      "integrity": "sha512-4krF8scpejhaOgqzBEcGM7yDIEfi0/8+8zDRZhNZZ2kjmHJ4hv3zCbQWxoJGz1iw5U0Jl0nma13xzHXcncMavQ=="
    }
  }
}

1

What version of rxjs is this? – Phix Nov 13 '18 at 03:05

ams · Answer 1 · 2018-11-13T22:14:46.773

Your imports are wrong and also the way you access the imports.

This should work:

StackBlitz

import { interval, from, zip } from 'rxjs';
import { repeat } from 'rxjs/operators';

const interval$ = interval(1000);
const items$ = from([1, 2, 3]);

const itemsOverTime$ = zip(interval$, items$).pipe(repeat());

itemsOverTime$.subscribe(([time, val]) => {
  console.log(val);
  // 1
  // 2
  // 3
  // 1
  // 2
  // 3
});

UPDATE: Here is a solution for CommonJS imports. You need to install rxjs-compat with npm, if you prefer to use the old syntax and imports. Look at this documentation Rxjs Doc.

Stackblitz

const Rx = require('rxjs/Rx');
const repeat = require('rxjs/operator/repeat');


const interval$ = Rx.Observable.interval(1000);
const items$ = Rx.Observable.from([1, 2, 3]);

const itemsOverTime$ = Rx.Observable.zip(interval$, items$).repeat();

itemsOverTime$.subscribe(([time, val]) => {
   console.log(val);
   // 1
   // 2
   // 3
   // 1
   // 2
   // 3
});

UPDATE 2:

For CommonJS and the new version of RxJs you need to do it like this:

StackBlitz

const Rx = require('rxjs');
const RxOp = require('rxjs/operators');

const interval$ = Rx.interval(1000);
const items$ = Rx.from([1, 2, 3]);

const itemsOverTime$ = Rx.zip(interval$, items$).pipe(RxOp.repeat());

itemsOverTime$.subscribe(([time, val]) => {
  console.log(val);
  // 1
  // 2
  // 3
  // 1
  // 2
  // 3
});

How should I set up my environment to support the `import`? I get `SyntaxError: Unexpected token import` because I am using nodejs, and there is no support for `import`. See answer here: https://stackoverflow.com/questions/39436322/node-js-syntaxerror-unexpected-token-import — Adam Cox, Nov 13 '18 at 14:21
@AdamCox I edited my answer to add a solution with CommonJs. — ams, Nov 13 '18 at 22:00

How to correctly declare or require in reference to the rxjs library?

1 Answers1