yeoman-generator/lib/util/binary-diff.js

Rails-inspired generator system that provides scaffolding for your apps

'use strict';
var fs = require('fs');
var readChunk = require('read-chunk');
var istextorbinary = require('istextorbinary');
var dateFormat = require('dateformat');
var prettyBytes = require('pretty-bytes');
var Table = require('cli-table');

module.exports = {
  isBinary: function (existingFilePath, newFileContents) {
    var existingHeader = readChunk.sync(existingFilePath, 0, 512);
    return istextorbinary.isBinarySync(undefined, existingHeader) || istextorbinary.isBinarySync(undefined, newFileContents);
  },

  diff: function (existingFilePath, newFileContents) {
    var existingStat = fs.statSync(existingFilePath);
    var table = new Table({
      head: ['', 'Existing', 'Replacement', 'Diff']
    });

    var sizeDiff;

    if (existingStat.size > newFileContents.length) {
      sizeDiff = '-';
    } else {
      sizeDiff = '+';
    }

    sizeDiff += prettyBytes(Math.abs(existingStat.size - newFileContents.length));

    table.push([
      'Size',
      prettyBytes(existingStat.size),
      prettyBytes(newFileContents.length),
      sizeDiff
    ], [
      'Last modified',
      dateFormat(existingStat.mtime),
      '',
      ''
    ]);

    return table.toString();
  }
};