gulp-dedupe

This plugin is checking for duplicate files (based on their name) in the stream and filter them or throw an error.

Install:

npm install gulp-dedupe --save-dev

Example:

var dedupe = require('gulp-dedupe');

...
    .pipe(dedupe()) // Remove duplicates from previous tasks (if any).
    .pipe(concat('bundle.css')) // For example, we need to concat the result without duplicates.
    .pipe(gulp.dest('./build'));

dedupe(options) optionally accepts options object. The following options are available:

• error to emit an error in case of duplicate (false by default).
• same to emit an error in case duplicates have different contents (true by default).
• diff to supply duplicates with different contents error from previous option with actual diff (false by default).