Colorized string diff ideal for text/code that spans through multiple lines.

This is basically just a wrapper around diff and ansi-styles + line numbers and omitting lines that don't have changes and/or that wouldn't help user identify the diff "context".

We also replace some invisible chars to make it easier to understand what really changed from one file to another:

• \r becomes <CR>
• \n becomes <LF>
• \t becomes <tab>

Created mainly to be used by esformatter and other tools that might need to display a nice looking diff of source files.

var disparity = require('disparity');

Diffs two blocks of text, comparing character by character and returns a String with ansi color codes.

var diff = disparity.chars(file1, file2);
console.log(diff);

Will return an empty string if oldStr === newStr;

// default options
var opts = {
  // how many lines to display before/after a line that contains diffs
  context: 3,
  // file paths displayed just before the diff
  paths: [disparity.removed, disparity.added]
};

Returns ansi colorized unified diff.

Will return an empty string if oldStr === newStr;

var diff = disparity.unified(file1, file2, {
  paths: ['test/file1.js', 'test/file2.js']
});
console.log(diff);

Returns unified diff. Useful for terminals that doesn't support colors.

Will return an empty string if oldStr === newStr;

var diff = disparity.unifiedNoColor(file1, file2, {
  paths: ['test/file1.js', 'test/file2.js']
});
console.log(diff);

String used on the diff headers to say that chars/lines was removed.

// default value
disparity.removed = 'removed';

String used on the diff headers to say that chars/lines was added.

// default value
disparity.added = 'added';

Object containing references to all the colors used by disparity.

If you want a different output than ansi (eg. HTML) you can replace the color values:

// wrap blocks into custom tags
disparity.colors = {
  // chars diff
  charsRemoved: { open: '<bggreen>', close: '</bggreen>' },
  charsAdded: { open: '<bgred>', close: '</bgred>' },

  // unified diff
  removed: { open: '<red>', close: '</red>' },
  added: { open: '<green>', close: '</green>' },
  header: { open: '<yellow>', close: '</yellow>' },
  section: { open: '<magenta>', close: '</magenta>' }
};

disparity also have a command line interface:

disparity [OPTIONS] <file_1> <file_2>

Options:
  -c, --chars           Output char diff (default mode).
  -u, --unified         Output unified diff.
  --unified-no-color    Don't output colors.
  -v, --version         Display current version.
  -h, --help            Display this help.

PS: cli can only compare 2 external files at the moment, no stdin support.

Released under the MIT license.