gulp-newer

A Gulp plugin for passing through only those source files that are newer than corresponding destination files.

Install

npm install gulp-newer --save-dev

Example

Using newer with 1:1 source:dest mappings

The default task in the example below sets up a watch that minifies images on changes. Piping the source files to newer before imagemin ensures that only those images that have changed are minified. The newer plugin is configured with the directory path for minified images.

var gulp = require('gulp');
var newer = require('gulp-newer');
var imagemin = require('gulp-imagemin');

var imgSrc = 'src/img/**';
var imgDest = 'build/img';

// Minify any new images
gulp.task('images', function() {

  // Add the newer pipe to pass through newer images only
  return gulp.src(imgSrc)
      .pipe(newer(imgDest))
      .pipe(imagemin())
      .pipe(gulp.dest(imgDest));

});

gulp.task('default', function() {
  gulp.watch(imgSrc, ['images']);
});

Using newer with many:1 source:dest mappings

Plugins like gulp-concat take many source files and generate a single destination file. In this case, the newer stream will pass through all source files if any one of them is newer than the destination file. The newer plugin is configured with the destination file path.

var gulp = require('gulp');
var newer = require('gulp-newer');
var concat = require('gulp-concat');

// Concatenate all if any are newer
gulp.task('concat', function() {

  // Add the newer pipe to pass through all sources if any are newer
  return gulp.src('lib/*.js')
      .pipe(newer('dist/all.js'))
      .pipe(concat('all.js'))
      .pipe(gulp.dest('dist'));

});

API

newer(dest)

• dest - string Path to destination directory or file.

newer(options)

• options.dest - string As above, required.
• options.ext - string Source files will be matched to destination files with the provided extension (e.g. '.css').
• options.map - function Map relative source paths to relative destination paths (e.g. function(relativePath) { return relativePath + '.bak'; })
• options.extra - string or array An extra file, file glob, or list of extra files and/or globs, to check for updated time stamp(s). If any of these files are newer than the destination files, then all source files will be passed into the stream.
• options.ctime - boolean Source files will be matched to destination files based on ctime rather than mtime.

Create a transform stream that passes through files whose modification time is more recent than the corresponding destination file's modification time.

If dest is a directory path, the newer stream will check for files in the destination directory with the same relative path as source files. Source files that have been modified more recently than the resolved destination file will be passed through. If the dest directory or resolved destination file does not exist, all source files will be passed through.

If dest is a file path, the newer stream will pass through all files if any one of them has been modified more recently than the destination file. If the dest file does not exist, all source files will be passed through.

By default, the newer stream will check files' modification time, or mtime, which updates when the file contents are changed. If ctime is true, files' change time will be checked instead, which updates when file contents or attributes like the file name or permissions have changed.