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- # big.js #
- A small, fast JavaScript library for arbitrary-precision decimal arithmetic.
- The little sister to [bignumber.js](https://github.com/MikeMcl/bignumber.js/).
- See also [decimal.js](https://github.com/MikeMcl/decimal.js/), and [here](https://github.com/MikeMcl/big.js/wiki) for the difference between them.
- ## Features
- - Faster, smaller and easier-to-use than JavaScript versions of Java's BigDecimal
- - Only 2.7 KB minified and gzipped
- - Simple API
- - Replicates the `toExponential`, `toFixed` and `toPrecision` methods of JavaScript's Number type
- - Includes a `sqrt` method
- - Stores values in an accessible decimal floating point format
- - No dependencies
- - Comprehensive [documentation](http://mikemcl.github.io/big.js/) and test set
- ## Load
- The library is the single JavaScript file *big.js* (or *big.min.js*, which is *big.js* minified).
- It can be loaded via a script tag in an HTML document for the browser
- <script src='./relative/path/to/big.js'></script>
- or as a CommonJS, [Node.js](http://nodejs.org) or AMD module using `require`.
- var Big = require('big.js');
- For Node.js, the library is available from the npm registry:
- $ npm install big.js
- ## 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: Big, the constructor of Big number instances.
- It accepts a value of type Number, String or Big number Object.
- x = new Big(123.4567)
- y = Big('123456.7e-3') // 'new' is optional
- z = new Big(x)
- x.eq(y) && x.eq(z) && y.eq(z) // true
- A Big number is immutable in the sense that it is not changed by its methods.
- 0.3 - 0.1 // 0.19999999999999998
- x = new Big(0.3)
- x.minus(0.1) // "0.2"
- x // "0.3"
- The methods that return a Big number can be chained.
- x.div(y).plus(z).times(9).minus('1.234567801234567e+8').plus(976.54321).div('2598.11772')
- x.sqrt().div(y).pow(3).gt(y.mod(z)) // true
- Like JavaScript's Number type, there are `toExponential`, `toFixed` and `toPrecision` methods.
- x = new Big(255.5)
- x.toExponential(5) // "2.55500e+2"
- x.toFixed(5) // "255.50000"
- x.toPrecision(5) // "255.50"
- The maximum number of decimal places and the rounding mode used to round the results of the `div`, `sqrt` and `pow`
- (with negative exponent) methods is determined by the value of the `DP` and `RM` properties of the `Big` number constructor.
- The other methods always give the exact result.
- (From *v3.0.0*, multiple Big number constructors can be created, see Change Log below.)
- Big.DP = 10
- Big.RM = 1
- x = new Big(2);
- y = new Big(3);
- z = x.div(y) // "0.6666666667"
- z.sqrt() // "0.8164965809"
- z.pow(-3) // "3.3749999995"
- z.times(z) // "0.44444444448888888889"
- z.times(z).round(10) // "0.4444444445"
- The value of a Big number is stored in a decimal floating point format in terms of a coefficient, exponent and sign.
- x = new Big(-123.456);
- x.c // [1,2,3,4,5,6] coefficient (i.e. significand)
- x.e // 2 exponent
- x.s // -1 sign
- For further information see the [API](http://mikemcl.github.io/big.js/) reference from the *doc* folder.
- ## Test
- The *test* directory contains the test scripts for each Big number method.
- The tests can be run with Node or a browser.
- To test a single method, from a command-line shell at the *test* directory, use e.g.
- $ node toFixed
- To test all the methods
- $ node every-test
- For the browser, see *single-test.html* and *every-test.html* in the *test/browser* directory.
- *big-vs-number.html* enables some of the methods of big.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.
- *big-vs-bigdecimal.html* tests the performance of big.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 big.js against the GWT version of
- BigDecimal from the npm registry.
- For example, to compare the time taken by the big.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
- ## Build
- I.e. minify.
- For Node, if uglify-js is installed globally ( `npm install uglify-js -g` ) then
- uglifyjs -o ./big.min.js ./big.js
- will create *big.min.js*.
- The *big.min.js* already present was created with *Microsoft Ajax Minifier 5.11*.
- ## TypeScript
- The [DefinitelyTyped](https://github.com/borisyankov/DefinitelyTyped) project has a TypeScript [definitions file](https://github.com/borisyankov/DefinitelyTyped/blob/master/big.js/big.js.d.ts) for big.js.
- The definitions file can be added to your project via the [big.js.TypeScript.DefinitelyTyped](https://www.nuget.org/packages/big.js.TypeScript.DefinitelyTyped/0.0.1) NuGet package or via [tsd](http://definitelytyped.org/tsd/).
- tsd query big.js --action install
- Any questions about the TypeScript definitions file should be addressed to the DefinitelyTyped project.
- ## Feedback
- Feedback is welcome.
- Bugs/comments/questions?
- Open an issue, or email
- Michael
- <a href="mailto:M8ch88l@gmail.com">M8ch88l@gmail.com</a>
- Bitcoin donation to:
- **1DppGRQSjVSMgGxuygDEHQuWEdTiVEzJYG**
- Thank you
- ## Licence
- See LICENCE.
- ## Change Log
- ####3.2.0
- * 14/09/17 Aid ES6 import.
- ####3.1.3
- * Minor documentation updates.
- ####3.1.2
- * README typo.
- ####3.1.1
- * API documentation update, including FAQ additions.
- ####3.1.0
- * Renamed and exposed `TO_EXP_NEG` and `TO_EXP_POS` as `Big.E_NEG` and
- `Big.E_POS`.
- ####3.0.2
- * Remove *.npmignore*, use `files` field in *package.json* instead.
- ####3.0.1
- * Added `sub`, `add` and `mul` aliases.
- * Clean-up after lint.
- ####3.0.0
- * 10/12/14 Added [multiple constructor functionality](http://mikemcl.github.io/big.js/#faq).
- * No breaking changes or other additions, but a major code reorganisation,
- so *v3* seemed appropriate.
- ####2.5.2
- * 1/11/14 Added bower.json.
- ####2.5.1
- * 8/06/14 Amend README requires.
- ####2.5.0
- * 26/01/14 Added `toJSON` method so serialization uses `toString`.
- ####2.4.1
- * 17/10/13 Conform signed zero to IEEEE 754 (2008).
- ####2.4.0
- * 19/09/13 Throw instances of `Error`.
- ####2.3.0
- * 16/09/13 Added `cmp` method.
- ####2.2.0
- * 11/07/13 Added 'round up' mode.
- ####2.1.0
- * 26/06/13 Allow e.g. `.1` and `2.`.
- ####2.0.0
- * 12/05/13 Added `abs` method and replaced `cmp` with `eq`, `gt`, `gte`, `lt`, and `lte` methods.
- ####1.0.1
- * Changed default value of MAX_DP to 1E6
- ####1.0.0
- * 7/11/2012 Initial release
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