Gulp task: replace <script src="node_modules/.../filename.js"> with <script src="lib/filename.js">

gulpfile.js

const replace = require('gulp-replace');

gulp.task('copy:index', ['clean'], function() {
  gulp.src(['index.html'])
    .pipe(replace(/node_modules(.*)\/(.*).js/g, 'lib/$2.js'))
    .pipe(gulp.dest('dist'));
});