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https://github.com/gvergnaud/rx-ease
Spring animation operator for rxjs 🦚✨
https://github.com/gvergnaud/rx-ease
animation damping interpolation observable operator reactive rxjs spring stiffness typescript
Last synced: 24 days ago
JSON representation
Spring animation operator for rxjs 🦚✨
- Host: GitHub
- URL: https://github.com/gvergnaud/rx-ease
- Owner: gvergnaud
- Created: 2018-05-13T16:42:22.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-01-04T04:04:21.000Z (almost 2 years ago)
- Last Synced: 2024-10-04T13:11:51.624Z (about 1 month ago)
- Topics: animation, damping, interpolation, observable, operator, reactive, rxjs, spring, stiffness, typescript
- Language: TypeScript
- Homepage:
- Size: 1.42 MB
- Stars: 22
- Watchers: 4
- Forks: 0
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# rx-ease
An animation operator for RxJs Observables!
- **Physic based**. The animation seemlessly interupts itself if a new value is emitted before it completes.
- **Performant**, emits on **requestAnimationFrame** at 60fps.
- **Typescript** first class support.
- **Versatile**, Works with any kind of data structures (Object, arrays, single values).
## Install
```
npm install rxjs rx-ease
```
## The gist
#### Interpolate between emitted numbers
You can simply use the `ease` operator in an observable pipeline. You need to configure the ease operator with two numbers: a **stiffness** value and a **damping** value. See [the presets sections](https://github.com/gvergnaud/rx-ease#presets) bellow for example of configurations.
```js
import { interval } from 'rxjs'
import { take, map, startWith } from 'rxjs/operators'
import ease from 'rx-ease'
const draw = x =>
Array(Math.floor(x))
.fill('#')
.join('')
const progress$ = interval(1000).pipe(
startWith(0),
map(i => * 100),
ease(120, 18),
map(draw)
)
progress$.subscribe(progress => console.log(progress))
// will log =>
// #
// ####
// ########
// #############
// #################
// ######################
// ##########################
// ##############################
// ##################################
// ######################################
// #########################################
// ############################################
// ##############################################
// ################################################
// ##################################################
// ####################################################
// #####################################################
// ######################################################
// #######################################################
// ########################################################
// #########################################################
// ##########################################################
// ##########################################################
// ##########################################################
// ##########################################################
```
#### Interpolate several properties of an object
If your Observable emits an object instead of a single number, you can use the `ease` operator to interpolate the values of one or several properties of this object. Just pass to `ease` an object of the same shape as the observed value with a config for each property you want to ease.
```js
import { fromEvent } from 'rxjs'
import { map } from 'rxjs/operators'
import ease from 'rx-ease'
const circle = document.querySelector('.circle')
const position$ = fromEvent(document, 'click').pipe(
map(e => ({ x: e.clientX, y: e.clientY })),
ease({
x: [120, 18],
y: [120, 18]
})
)
position$.subscribe(({ x, y }) => {
circle.style.transform = `translate(${x}px, ${y}px)`
})
```
## Api
Similarly to [react-motion](https://github.com/chenglou/react-motion), rx-ease is a **spring animation** operator. To configure the animation you need to pass a stiffness and a damping value in an array like `[stiffness, damping]` (for example `[120, 18]`).
#### Easing a single value
##### signature
```ts
type Config = [number, number]
ease: (config: Config) => (stream: Observable) => Observable
```
##### example
```js
import { interval } from 'rxjs'
import ease from 'rx-ease'
const easedInterval$ = interval(1000).pipe(
map(x => x * 100),
ease([170, 26])
)
```
#### Easing values of an array
##### signature
```ts
ease: (config: Config[]) => (stream: Observable) => Observable
```
##### example
```js
import { fromEvent } from 'rxjs'
import ease from 'rx-ease'
const easedMousePosition$ = fromEvent(window, 'mousemove').pipe(
map(e => [e.clientX, e.clientY]),
ease([
[170, 26],
[170, 26],
])
)
```
#### Easing properties of an object
##### signature
```ts
ease: (config: Record) => (stream: Observable>) => Observable>
```
##### example
```js
import { fromEvent } from 'rxjs'
import ease from 'rx-ease'
const easedMousePosition$ = fromEvent(window, 'mousemove').pipe(
map(e => ({
x: e.clientX,
y: e.clientY
}),
ease({
x: [170, 26],
y: [170, 26],
})
)
```
#### presets
- **noWobble**: equivalent to passing `[170, 26]`
- **gentle**: equivalent to passing `[120, 14]`
- **wobbly**: equivalent to passing `[180, 12]`
- **stiff**: equivalent to passing `[210, 20]`
```js
import ease, { presets } from 'rx-ease'
interval(1000).pipe(
map(x => x * 100),
ease(...presets.stiff)
)
```
## Credits
This was heavily inspired by @chenglou's [react-motion](https://github.com/chenglou/react-motion).