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readme.md
normalize-range
Utility for normalizing a numeric range, with a wrapping function useful for polar coordinates.
Usage
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.
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.
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.
curry(min, max, [minExclusive], [maxExclusive])
Convenience method for currying all method arguments except value
.
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