149 lines
3.9 KiB
Markdown
149 lines
3.9 KiB
Markdown
|
# 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)
|