live-moving-average/readme.md

An ever updating average of the last n values.

# live-moving-average

**An ever updating average of the last n values.** See [Moving Average](https://en.wikipedia.org/wiki/Moving_average).

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Reuses the values array to prevent GC-thrashing. Does not slow down with an increasing window size:

```window size 10, 1 push, 1 get x 65,514,574 ops/sec ±0.62% (90 runs sampled)
window size 10, 1 push, 10 get x 49,988,485 ops/sec ±0.28% (93 runs sampled)
window size 1000, 1 push, 1 get x 64,048,288 ops/sec ±0.42% (93 runs sampled)
window size 100, 1 push, 10 get x 49,012,149 ops/sec ±0.40% (95 runs sampled)
```


## Installing

```shell
npm install live-moving-average
```


## Usage

```js
const createWindow = require('live-moving-average')

const avg = createWindow(3, 0) // size of 3, fill with 0

// using api fluently
avg
    .push(2)
    .push(3)
    .push(4)
    .get() // 3, because (2 + 3 + 4) / 3

avg.push(5)
avg.push(6)
avg.get() // 5, because (4 + 5 + 6) / 3

avg.push(7)
avg.get() // 6, because (5 + 6 + 7) / 3
```


## API

### `const w = createWindow(size, fill = 0)`

`size` and `fill` must be a number.

### `w.push(val)`

`val` must be a number.    
Returns `w`.

### `w.get()`

Returns the moving average.


## Contributing

If you have a question or need support using `live-moving-average`, please double-check your code and setup first. If you think you have found a bug or want to propose a feature, use [the issues page](https://github.com/derhuerst/live-moving-average/issues).