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# normalize-range
Utility for normalizing a numeric range, with a wrapping function useful for polar coordinates.
[](https://travis-ci.org/jamestalmage/normalize-range)
[](https://coveralls.io/github/jamestalmage/normalize-range?branch=master)
[](https://codeclimate.com/github/jamestalmage/normalize-range)
[](https://david-dm.org/jamestalmage/normalize-range)
[](https://david-dm.org/jamestalmage/normalize-range#info=devDependencies)
[](https://nodei.co/npm/normalize-range/)
## Usage
```js
var nr = require('normalize-range');
nr.wrap(0, 360, 400);
//=> 40
nr.wrap(0, 360, -90);
//=> 270
nr.limit(0, 100, 500);
//=> 100
nr.limit(0, 100, -20);
//=> 0
// There is a convenient currying function
var wrapAngle = nr.curry(0, 360).wrap;
var limitTo10 = nr.curry(0, 10).limit;
wrapAngle(-30);
//=> 330
```
## API
### wrap(min, max, value)
Normalizes a values that "wraps around". For example, in a polar coordinate system, 270˚ can also be
represented as -90˚.
For wrapping purposes we assume `max` is functionally equivalent to `min`, and that `wrap(max + 1) === wrap(min + 1)`.
Wrap always assumes that `min` is *inclusive*, and `max` is *exclusive*.
In other words, if `value === max` the function will wrap it, and return `min`, but `min` will not be wrapped.
```js
nr.wrap(0, 360, 0) === 0;
nr.wrap(0, 360, 360) === 0;
nr.wrap(0, 360, 361) === 1;
nr.wrap(0, 360, -1) === 359;
```
You are not restricted to whole numbers, and ranges can be negative.
```js
var π = Math.PI;
var radianRange = nr.curry(-π, π);
redianRange.wrap(0) === 0;
nr.wrap(π) === -π;
nr.wrap(4 * π / 3) === -2 * π / 3;
```
### limit(min, max, value)
Normalize the value by bringing it within the range.
If `value` is greater than `max`, `max` will be returned.
If `value` is less than `min`, `min` will be returned.
Otherwise, `value` is returned unaltered.
Both ends of this range are *inclusive*.
### test(min, max, value, [minExclusive], [maxExclusive])
Returns `true` if `value` is within the range, `false` otherwise.
It defaults to `inclusive` on both ends of the range, but that can be
changed by setting `minExclusive` and/or `maxExclusive` to a truthy value.
### validate(min, max, value, [minExclusive], [maxExclusive])
Returns `value` or throws an error if `value` is outside the specified range.
### name(min, max, value, [minExclusive], [maxExclusive])
Returns a string representing this range in
[range notation](https://en.wikipedia.org/wiki/Interval_(mathematics)#Classification_of_intervals).
### curry(min, max, [minExclusive], [maxExclusive])
Convenience method for currying all method arguments except `value`.
```js
var angle = require('normalize-range').curry(-180, 180, false, true);
angle.wrap(270)
//=> -90
angle.limit(200)
//=> 180
angle.test(0)
//=> true
angle.validate(300)
//=> throws an Error
angle.toString() // or angle.name()
//=> "[-180,180)"
```
#### min
*Required*
Type: `number`
The minimum value (inclusive) of the range.
#### max
*Required*
Type: `number`
The maximum value (exclusive) of the range.
#### value
*Required*
Type: `number`
The value to be normalized.
#### returns
Type: `number`
The normalized value.
## Building and Releasing
- `npm test`: tests, linting, coverage and style checks.
- `npm run watch`: autotest mode for active development.
- `npm run debug`: run tests without coverage (istanbul can obscure line #'s)
Release via `cut-release` tool.
## License
MIT © [James Talmage](http://github.com/jamestalmage)
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