> For the complete documentation index, see [llms.txt](https://www.learnrxjs.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.learnrxjs.io/learn-rxjs/operators/creation/from.md).

# from

\`\`# from

**signature: `from(ish: ObservableInput, mapFn: function, thisArg: any, scheduler: Scheduler): Observable`**

### Turn an array, promise, or iterable into an observable.

***

💡 This operator can be used to convert a promise to an observable!

💡 For arrays and iterables, all contained values will be emitted as a sequence!

💡 This operator can also be used to emit a string as a sequence of characters!

***

#### Examples

**Example 1: Observable from array**

( [StackBlitz](https://stackblitz.com/edit/typescript-sckwsw?file=index.ts\&devtoolsheight=100) | [jsBin](http://jsbin.com/foceyuketi/1/edit?js,console) | [jsFiddle](https://jsfiddle.net/btroncone/o7kb5e6j/) )

```js
// RxJS v6+
import { from } from 'rxjs';

//emit array as a sequence of values
const arraySource = from([1, 2, 3, 4, 5]);
//output: 1,2,3,4,5
const subscribe = arraySource.subscribe(val => console.log(val));
```

**Example 2: Observable from promise**

( [StackBlitz](https://stackblitz.com/edit/typescript-clpg1f?file=index.ts\&devtoolsheight=100) | [jsBin](http://jsbin.com/tamofinujo/1/edit?js,console) | [jsFiddle](https://jsfiddle.net/btroncone/2czc5sae/) )

```js
// RxJS v6+
import { from } from 'rxjs';

//emit result of promise
const promiseSource = from(new Promise(resolve => resolve('Hello World!')));
//output: 'Hello World'
const subscribe = promiseSource.subscribe(val => console.log(val));
```

**Example 3: Observable from collection**

( [StackBlitz](https://stackblitz.com/edit/typescript-drfckx?file=index.ts\&devtoolsheight=100) | [jsBin](http://jsbin.com/tezohobudu/1/edit?js,console) | [jsFiddle](https://jsfiddle.net/btroncone/ae6hu9a8/) )

```js
// RxJS v6+
import { from } from 'rxjs';

//works on js collections
const map = new Map();
map.set(1, 'Hi');
map.set(2, 'Bye');

const mapSource = from(map);
//output: [1, 'Hi'], [2, 'Bye']
const subscribe = mapSource.subscribe(val => console.log(val));
```

**Example 4: Observable from string**

( [StackBlitz](https://stackblitz.com/edit/typescript-19nejh?file=index.ts\&devtoolsheight=100) | [jsBin](http://jsbin.com/wenozubana/1/edit?js,console) | [jsFiddle](https://jsfiddle.net/btroncone/hfvzjcvL/) )

```js
// RxJS v6+
import { from } from 'rxjs';

//emit string as a sequence
const source = from('Hello World');
//output: 'H','e','l','l','o',' ','W','o','r','l','d'
const subscribe = source.subscribe(val => console.log(val));
```

#### Related Recipes

* [HTTP Polling](/learn-rxjs/recipes/http-polling.md)
* [Lockscreen](/learn-rxjs/recipes/lockscreen.md)
* [Memory Game](/learn-rxjs/recipes/memory-game.md)
* [Progress Bar](/learn-rxjs/recipes/progressbar.md)

#### Additional Resources

* [from](https://rxjs.dev/api/index/function/from) 📰 - Official docs
* [Creation operators: from, fromArray, fromPromise](https://egghead.io/lessons/rxjs-creation-operators-from-fromarray-frompromise?course=rxjs-beyond-the-basics-creating-observables-from-scratch) 🎥 💵 - André Staltz

***

> 📁 Source Code: <https://github.com/ReactiveX/rxjs/blob/master/src/internal/observable/from.ts>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://www.learnrxjs.io/learn-rxjs/operators/creation/from.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.