Update to Readme to reflect node require |
||
---|---|---|
doc | ||
perf | ||
test | ||
.npmignore | ||
.travis.yml | ||
LICENCE | ||
README.md | ||
bignumber.js | ||
bignumber.min.js | ||
package.json |
README.md
bignumber.js
A JavaScript library for arbitrary-precision decimal and non-decimal arithmetic.
Features
- Faster, smaller, and perhaps easier to use than JavaScript versions of Java's BigDecimal
- 5 KB minified and gzipped
- Simple API but full-featured
- Works with numbers with or without fraction digits in bases from 2 to 64 inclusive
- Replicates the
toExponential
,toFixed
,toPrecision
andtoString
methods of JavaScript's Number type - Includes a
toFraction
and a correctly-roundedsquareRoot
method - Stores values in an accessible decimal floating point format
- No dependencies
- Comprehensive documentation and test set
If an even smaller and simpler library is required see big.js.
It's half the size but only works with decimal numbers and only has half the methods.
It also does not allow NaN
or Infinity
, or have the configuration options of this library.
See also decimal.js.
Load
The library is the single JavaScript file bignumber.js (or minified, bignumber.min.js).
It can be loaded via a script tag in an HTML document for the browser
<script src='./relative/path/to/bignumber.js'></script>
or as a CommonJS, Node.js or AMD module using require
.
For Node, put the bignumber.js file into the same directory as the file that is requiring it and use
var BigNumber = require('./bignumber');
or put it in a node_modules directory within the directory and use require('bignumber.js')
.
The library is also available from the npm registry, so
$ npm install bignumber.js
will install this directory in a node_modules directory within the current directory.
To load with AMD loader libraries such as requireJS:
require(['path/to/bignumber'], function(BigNumber) {
// Use BigNumber here in local scope. No global BigNumber.
});
Use
In all examples below, var
, semicolons and toString
calls are not shown.
If a commented-out value is in quotes it means toString
has been called on the preceding expression.
The library exports a single function: BigNumber, the constructor of BigNumber instances.
It accepts a value of type Number (up to 15 significant digits only), String or BigNumber Object,
x = new BigNumber(123.4567)
y = BigNumber('123456.7e-3') // 'new' is optional
z = new BigNumber(x)
x.equals(y) && y.equals(z) && x.equals(z) // true
and a base from 2 to 64 inclusive can be specified.
x = new BigNumber(1011, 2) // "11"
y = new BigNumber('zz.9', 36) // "1295.25"
z = x.plus(y) // "1306.25"
A BigNumber is immutable in the sense that it is not changed by its methods.
0.3 - 0.1 // 0.19999999999999998
x = new BigNumber(0.3)
x.minus(0.1) // "0.2"
x // "0.3"
The methods that return a BigNumber can be chained.
x.dividedBy(y).plus(z).times(9).floor()
x.times('1.23456780123456789e+9').plus(9876.5432321).dividedBy('4444562598.111772').ceil()
Method names over 5 letters in length have a shorter alias.
x.squareRoot().dividedBy(y).toPower(3).equals(x.sqrt().div(y).pow(3)) // true
x.cmp(y.mod(z).neg()) == 1 && x.comparedTo(y.modulo(z).negated()) == 1 // true
Like JavaScript's Number type, there are toExponential
, toFixed
and toPrecision
methods
x = new BigNumber(255.5)
x.toExponential(5) // "2.55500e+2"
x.toFixed(5) // "255.50000"
x.toPrecision(5) // "255.50"
x.toNumber() // 255.5
and a base can be specified for toString
.
x.toString(16) // "ff.8"
The maximum number of decimal places of, and the rounding mode applied to, the results of operations involving division (i.e. division, square root, base conversion, and negative power operations) is set by a configuration object passed to the config
method of the BigNumber
constructor.
The other arithmetic operations always give the exact result.
BigNumber.config({ DECIMAL_PLACES: 10, ROUNDING_MODE: 4 })
// Alternatively, BigNumber.config( 10, 4 );
x = new BigNumber(2);
y = new BigNumber(3);
z = x.div(y) // "0.6666666667"
z.sqrt() // "0.8164965809"
z.pow(-3) // "3.3749999995"
z.toString(2) // "0.1010101011"
z.times(z) // "0.44444444448888888889"
z.times(z).round(10) // "0.4444444445"
There is a toFraction
method with an optional maximum denominator argument
y = new BigNumber(355)
pi = y.dividedBy(113) // "3.1415929204"
pi.toFraction() // [ "7853982301", "2500000000" ]
pi.toFraction(1000) // [ "355", "113" ]
and isNaN
and isFinite
methods, as NaN
and Infinity
are valid BigNumber
values.
x = new BigNumber(NaN) // "NaN"
y = new BigNumber(Infinity) // "Infinity"
x.isNaN() && !y.isNaN() && !x.isFinite() && !y.isFinite() // true
The value of a BigNumber is stored in a decimal floating point format in terms of a coefficient, exponent and sign.
x = new BigNumber(-123.456);
x.c // "1,2,3,4,5,6" coefficient (i.e. significand)
x.e // 2 exponent
x.s // -1 sign
For futher information see the API reference from the doc folder.
Test
The test directory contains the test scripts for each method.
The tests can be run with Node or a browser.
For a quick test of all the methods, from a command-line shell at the test/ directory
$ node quick-test
To test a single method in more depth, e.g.
$ node toFraction
To test all the methods in more depth
$ node every-test
For the browser, see quick-test.html, single-test.html and every-test.html in the test/browser directory.
bignumber-vs-number.html enables some of the methods of bignumber.js to be compared with those of JavaScript's Number type.
Performance
The perf directory contains two applications and a lib directory containing the BigDecimal libraries used by both.
bignumber-vs-bigdecimal.html tests the performance of bignumber.js against the JavaScript translations of two versions of BigDecimal, its use should be more or less self-explanatory. (The GWT version doesn't work in IE 6.)
- GWT: java.math.BigDecimal
https://github.com/iriscouch/bigdecimal.js - ICU4J: com.ibm.icu.math.BigDecimal
https://github.com/dtrebbien/BigDecimal.js
The BigDecimal in Node's npm registry is the GWT version. Despite its seeming popularity I have found it to have some serious bugs, see the Node script perf/lib/bigdecimal_GWT/bugs.js for examples of flaws in its remainder, divide and compareTo methods.
bigtime.js is a Node command-line application which tests the performance of bignumber.js against the GWT version of BigDecimal from the npm registry.
For example, to compare the time taken by the bignumber.js plus
method and the BigDecimal add
method:
$ node bigtime plus 10000 40
This will time 10000 calls to each, using operands of up to 40 random digits and will check that the results match.
For help:
$ node bigtime -h
See the README in the directory for more information.
Build
I.e. minify.
For Node, if uglify-js is installed globally ( npm install uglify-js -g
) then
npm run build
will create bignumber.min.js.
Feedback
Open an issue, or email
Michael
M8ch88l@gmail.com
Bitcoin donation to:
1CauoGYrEoJFhcyxGVaiLTE6f3WCaSUjnm
Thank you
Licence
MIT.
See LICENCE.
Change Log
####1.4.0
- 08/05/2014 Added
toNumber
.
####1.3.0
- 08/11/2013 Ensure correct rounding of
sqrt
in all, rather than almost all, cases. - Maximum radix to 64.
####1.2.1
- 17/10/2013 Sign of zero when x < 0 and x + (-x) = 0.
####1.2.0
- 19/9/2013 Throw Error objects for stack.
####1.1.1
- 22/8/2013 Show original value in constructor error message.
####1.1.0
- 1/8/2013 Allow numbers with trailing radix point.
####1.0.1
- Bugfix: error messages with incorrect method name
####1.0.0
- 8/11/2012 Initial release