diff

Computes the differences between adjacent elements in an array of values.

Installation

$ npm install compute-diff

For use in the browser, use browserify.

Usage

To use the module,

var diff = require( 'compute-diff' );

diff( arr )

Computes the differences between adjacent array values.

var data = [ 1, 3, 2, 10, 5 ];

var vals = diff( data );
// returns [ -2, 1, -8, 5 ]

Note: the returned array will have a length which is one less than the original array; i.e., if arr.length = 10, then diff( arr ).length = 9.

Examples

var diff = require( 'compute-diff' );

var data = new Array( 100 );
for ( var i = 0; i < data.length; i++ ) {
	data[ i ] = Math.round( Math.random() * 100 );
}

console.log( diff( data ) );

To run the example code from the top-level application directory,

$ node ./examples/index.js

Tests

Unit

Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov

License

MIT license.

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Copyright

Copyright © 2014. Athan Reines.