Observables and promises are both used to handle async activity in JavaScript. Creation defines the behaviour of a promise/observable and the values that are emitted, and usage … I realize that promise and observable are used for Asynchronous operations. So it makes sense to convert a list of promises into an observable. A promise in JavaScript is a native feature that was introduced in ECMAScript 6. Promises are created using the promise constructor. Observable have the same feature set as Promises plus additional features we will cover next. The Angular framework uses a lot of RxJS. 95% of the time I see code using it, it's a one-off that could have just been a promise. The first time when i read Promise and Observable, there are some confusions. Observable vs Promise | When to use Promise Observable vs Promise | When to use Observable. Have a look at code to better understand. Then we can do nice things on it, like .every(… List of contents: Introduction Promise Convert Observable to Promise Observable Observables for component interaction When use Promise and when use Observable Introduction Both Promises and Observables are special type of objects that with their abstractions provide a behavior to help us make our applications runs in an asynchronous way, allowing it to perform multiple operations … Promises have their own methods which are then and catch. Compared to a promise, an observable can be canceled. This blog covers the difference between observable and Promises observable and promises in Javascript with examples. As you can see the Observable API is very similar to the Promise API. An observable is a flow of past and future values. The subscribe() method similar to the Promise then() will pass the value to our function when the async task has completed. Here are the key differences between observables and promises: Eager vs Lazy. After it is created, it is typically passed to someone else who uses it. An Observable can do everything that a Promise can do, plus more. ### ### Promises vs Observables in JavaScript Native vs Non-Native. A promise/observable is an object that first of all needs to be created by someone. The forEach() method returns… a promise! so we can simply do a .then() on the result of forEach() which will be invoked when the observable has fully completed. RxJS is all about unifying the ideas of promise callbacks and data flow and making them easier to work with. But wait, if they are the same, why it’s not just be Promise or just be Observable :)). A promise is a future value. Promises are objects that promise they will have value in the near future - either a success or failure. Observables provides operators like map.forEach, reduce,...similar to an array. This article differentiates the properties of a JavaScript Promise with an Observable. Use Angular’s HttpClient to handle API calls. 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