Join Operators

• Join operators combine multiple observables into a single observable
• Most are creation operators, though some are pipeable
• Like the mapping operators, they differ in how they handle concurrency and completion

merge

• Merges two or more observables
• Observables run concurrently
• The resultant observable completes when all merged observables complete

merge(of(1, 2, 3), of('a', 'b', 'c'));

combineLatest

• Merges two or more observables
• Emits an array of the latest values from all supplied observables
• Completes when all combined observables complete

combineLatest(interval(300), interval(500), interval(1_000));

concat

• Merges two or more observables
• Runs each observable sequentially
• Only one observable runs at a time
• Completes when all combined observables complete

concat(of(1, 2, 3), of(4, 5, 6), of(7, 8, 9));