bollinger-bands/README.md

Fintach math utility to calculate bollinger bands.

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# MAINTENANCE WARNING

This module is lack of maintenance.

If you are familiar with python programming maybe you could check [**stock-pandas**](https://github.com/kaelzhang/stock-pandas) which provides powerful statistic indicators support, and is backed by [`numpy`](https://numpy.org/) and [`pandas`](https://pandas.pydata.org/).

The performance of [**stock-pandas**](https://github.com/kaelzhang/stock-pandas) is many times higher than JavaScript libraries, and can be directly used by machine learning programs.

****

# bollinger-bands

Fintach math utility to calculate [bollinger bands](https://en.wikipedia.org/wiki/Bollinger_Bands).

## Install

```sh
$ npm install bollinger-bands
```

## Usage

```js
import boll from 'bollinger-bands'

boll([1, 2, 4, 8], 2, 2)
// {
//   upper: [, 2.5, 5, 10],
//   mid  : [, 1.5, 3, 6],
//   lower: [, 0.5, 1, 2]
// }
```

## boll(datum, size, times, options)

- **datum** `Array.<Number>` the collection of data
- **size** `Number=20` the period size, defaults to `20`
- **times** `Number=2` the times of standard deviation between the upper band and the moving average.
- **options** `Object=` optional options
  - ma `Array.<Number>=` the moving averages of the provided `datum` and period `size`. This option is used to prevent duplicate calculation of moving average.
  - sd `Array.<Number>=` the standard average of the provided `datum` and period `size`

Returns `Array.<Band>` the array of the `Band` object.

### struct `Band`

- **upper** `Number` the value of the upper band
- **mid** `Number` the value middle band (moving average)
- **lower** `Number` the value of the lower band

## Related Fintech Modules

- [moving-averages](https://www.npmjs.com/package/moving-averages): The complete collection of utility methods for [Moving average](https://en.wikipedia.org/wiki/Moving_average).
- [s-deviation](https://www.npmjs.com/package/s-deviation): Math utility to calculate standard deviations.

## License

MIT