A quick node tool to copy a sequence of images from one folder to another, in reverse order. '0001.exr' -> '0048.exr', '0048.exr' -> '0001.exr'

file_sequence_reverser.js

var fs = require('fs'),
	path = require('path'),
	inputPath = '4',
	outputPath = '4-reversed',
	suffix = 'exr',
	startFrame = 1,
	endFrame = 48,
	paddingZeroes = 4,
	pad = function (num, size) {
		var s = num+"";
		while (s.length < size) s = "0" + s;
		return s;
	},
	listProcessor = function(err, fileNameList){
		if(err){throw err;}
		fileNameList.forEach(function (fileName) {
			var split = fileName.split('.'),
				newName = pad(startFrame + endFrame - parseInt(split[0], 10), 4) + '.' + split[1];
			if(split[1] !== suffix){
				console.log(fileName + ' was not the correct type, so it was not processed.');
			}

			fs.createReadStream(
				path.join(inputPath, fileName)
			).pipe(
				fs.createWriteStream(
					path.join(outputPath, newName)
				).on(
					'finish',
					function() {
						console.log(fileName, '->', newName);
					}
				)
			);
		});
	};

fs.readdir(inputPath, listProcessor);