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