error TS2339: Property 'combineLatest' does not exist on type 'typeof Observable'

Question

I have a problem when I try to start my angular 6 project. I've got this error :

"TSError: ⨯ Unable to compile TypeScript: git.version.ts(34,29): error TS2339: Property 'combineLatest' does not exist on type 'typeof Observable'."

It worked well with Angular 5 but I updated RxJs (from 5 to 6) and now it doesn't work.

import { readFileSync, writeFileSync } from 'fs';
import { join } from 'path';
import { Observable, combineLatest } from 'rxjs';


let exec = require('child_process').exec;

let tag = new Observable<string>(s => {
    exec('git describe --tags $(git rev-list --tags --max-count=1)',
        function (error: Error, stdout: Buffer, stderr: Buffer) {
            if (error !== null) {
                console.log('git error: ' + error + stderr);
            }
            s.next(stdout.toString().trim());
            s.complete();
        });
});



let revision = new Observable<string>(s => {
    exec('git rev-parse --short HEAD',
        function (error: Error, stdout: Buffer, stderr: Buffer) {
            if (error !== null) {
                console.log('git error: ' + error + stderr);
            }
            s.next(stdout.toString().trim());
            s.complete();
        });
});

Observable.combineLatest(tag, revision).subscribe(([tag, revision]) => {
        console.log(`version: '${tag}', revision: '${revision}'`);

        const content = '// this file is automatically generated\n' +
            `export const version = {version: '${tag}', revision: '${revision}'};`;

        writeFileSync(
            'src/environments/version.ts',
            content,
            {encoding: 'utf8'}
        );
    });

The command I launch : "ts-node git.version.ts" is to get the commit and the tag version I work with.

Thank you very much !

UPDATE :

combineLatest(tag, revision).subscribe(([tag, revision]) => {
        console.log(`version: '${tag}', revision: '${revision}'`);

        const content = '// this file is automatically generated\n' +
            `export const version = {version: '${tag}', revision: '${revision}'};`;

        writeFileSync(
            'src/environments/version.ts',
            content,
            {encoding: 'utf8'}
        );
    });

I haven't any error about CombineLatest but I have an error from ts-node :

function (exports, require, module, __filename, __dirname) { import { writeFileSync } from 'fs';
                                                              ^^^^^^

SyntaxError: Unexpected token import

Any idea ?

UPDATE 2 : To fix this error :

"config": "ts-node -O '{\"module\": \"commonjs\"}' git.version.ts",

In package.json

Z. Bagley Z. Bagley · Accepted Answer · 2018-08-21T14:57:03

Angular6 comes with rxjs6. This is the proper format for combineLatest:

import before class declaration from the new 'rxjs' location:

// RxJS v6+
import { timer, combineLatest } from 'rxjs';

example of use inside a function:

//timerOne emits first value at 1s, then once every 4s
const timerOne = timer(1000, 4000);
//timerTwo emits first value at 2s, then once every 4s
const timerTwo = timer(2000, 4000);
//timerThree emits first value at 3s, then once every 4s
const timerThree = timer(3000, 4000);

//when one timer emits, emit the latest values from each timer as an array
const combined = combineLatest(timerOne, timerTwo, timerThree);

const subscribe = combined.subscribe(
  ([timerValOne, timerValTwo, timerValThree]) => {
    /*
      Example:
    timerOne first tick: 'Timer One Latest: 1, Timer Two Latest:0, Timer Three Latest: 0
    timerTwo first tick: 'Timer One Latest: 1, Timer Two Latest:1, Timer Three Latest: 0
    timerThree first tick: 'Timer One Latest: 1, Timer Two Latest:1, Timer Three Latest: 1
  */
    console.log(
      `Timer One Latest: ${timerValOne},
     Timer Two Latest: ${timerValTwo},
     Timer Three Latest: ${timerValThree}`
    );
  }
);

Of course, in your case you'd replace the timers with your tag, revision items.

Code excerpt from:

https://www.learnrxjs.io/operators/combination/combinelatest.html

which contains more examples

error TS2339: Property 'combineLatest' does not exist on type 'typeof Observable'

2 Answers