okiba-gang/okiba

# Okiba / math
Collection of math functions

__



### Installation

```bash
npm i --save @okiba/math
```

Or import it directly in the browser
```html
<script type="module" src="https://unpkg.com/@okiba/math/index.js"></script>
```

## Usage

```javascript
import math from '@okiba/math'
```

#### Untranspiled code 🛑
Okiba Core packages are not transpiled, so _don't forget to transpile them with your favourite bundler_.
For example, using Babel with Webpack, you should prevent imports from okiba to be excluded from transpilation, like follows:

```javascript
{
  test: /\.js$/,
  exclude: /node_modules\/(?!(@okiba)\/).*/,
  use: {
    loader: 'babel-loader',
    options: {
      presets: ['@babel/preset-env']
    }
  }
}
```







## lerp(min, max, fraction)


Linear interpolation between a two values






```javascript
import {lerp} from '@okiba/math'
const xPosition = lerp(0, 100, 0.5)
console.log(xPosition) // 50
```




#### Arguments


##### + `min`: `Number`

Minimum possible value


##### + `max`: `Number`

Maximum possible value


##### + `fraction`: `Number`

Current position





#### Returns

`Number` The interpolated value
## map(n, min1, max1, min2, max2)


Maps a value between two ranges






```javascript
import {map} from '@okiba/math'

const x = map(0.5, 0, 1, 0, 1000)
console.log(x) // 500

const y = map(0, -1, 1, -1000, 1000)
console.log(y) // 0
```




#### Arguments


##### + `n`: `Number`

Value to map


##### + `min1`: `Number`

Source range minimum


##### + `max1`: `Number`

Source range maximum


##### + `min2`: `Number`

Target range minimum


##### + `max2`: `Number`

Target range maximum





#### Returns

`Number` Mapped value
## cap(n, min, max)


Limit a value between a min and a max (inclusive)






```javascript
import {cap} from '@okiba/math'
let progress = 1.1
progress = cap(0, 1, progress)
console.log(progress) // 1
```




#### Arguments


##### + `n`: `Number`

Value to cap


##### + `min`: `Number`

Minimum possible value


##### + `max`: `Number`

Maximum possible value





#### Returns

`Number` Capped value
## distance(x1, x2)


Distance between two numbers






```javascript
import {distance} from '@okiba/math'
const x1 = -100, x2 = 100
const d = distance(x1, x2)
console.log(d) // 200
```




#### Arguments


##### + `x1`: `Number`

First number


##### + `x2`: `Number`

Second number





#### Returns

`Number` Distance between the values
## round(n, p)


Round a number with given precision, with memoized powers






```javascript
import {round} from '@okiba/math'
const rounded = distance(1.111111, 3)
console.log(rounded) // 1.111
```




#### Arguments


##### + `n`: `Number`

Number to round


##### + `p`: `Number` | _optional_ - _default_: `3`

Precision of digits to leave





#### Returns

`Number` Rounded number