Как подключить библиотеку из node_modules

var gulp = require('gulp'); 
var sass = require('gulp-sass'); 
var browserSync = require('browser-sync'); 
var useref = require('gulp-useref'); 
var uglify = require('gulp-uglify'); 
var gulpIf = require('gulp-if'); 
var cssnano = require('gulp-cssnano'); 
var imagemin = require('gulp-imagemin'); 
var cache = require('gulp-cache'); 
var del = require('del'); 
var runSequence = require('run-sequence'); 
 
// Basic Gulp task syntax 
gulp.task('hello', function() { 
  console.log('Hello Zell!'); 
}) 
 
// Development Tasks  
// ----------------- 
 
// Start browserSync server 
gulp.task('browserSync', function() { 
  browserSync({ 
    server: { 
      baseDir: 'app' 
    } 
  }) 
}) 
 
gulp.task('sass', function() { 
  return gulp.src('app/scss/**/*.scss') // Gets all files ending with .scss in app/scss and children dirs 
    .pipe(sass().on('error', sass.logError)) // Passes it through a gulp-sass, log errors to console 
    .pipe(gulp.dest('app/css')) // Outputs it in the css folder 
    .pipe(browserSync.reload({ // Reloading with Browser Sync 
      stream: true 
    })); 
}) 
 
// Watchers 
gulp.task('watch', function() { 
  gulp.watch('app/scss/**/*.scss', ['sass']); 
  gulp.watch('app/*.html', browserSync.reload); 
  gulp.watch('app/js/**/*.js', browserSync.reload); 
}) 
 
// Optimization Tasks  
// ------------------ 
 
// Optimizing CSS and JavaScript  
gulp.task('useref', function() { 
 
  return gulp.src('app/*.html') 
    .pipe(useref()) 
    .pipe(gulpIf('*.js', uglify())) 
    .pipe(gulpIf('*.css', cssnano())) 
    .pipe(gulp.dest('dist')); 
}); 
 
// Optimizing Images  
gulp.task('images', function() { 
  return gulp.src('app/images/**/*.+(png|jpg|jpeg|gif|svg)') 
    // Caching images that ran through imagemin 
    .pipe(cache(imagemin({ 
      interlaced: true, 
    }))) 
    .pipe(gulp.dest('dist/images')) 
}); 
 
// Copying fonts  
gulp.task('fonts', function() { 
  return gulp.src('app/fonts/**/*') 
    .pipe(gulp.dest('dist/fonts')) 
}) 
 
// Cleaning  
gulp.task('clean', function() { 
  return del.sync('dist').then(function(cb) { 
    return cache.clearAll(cb); 
  }); 
}) 
 
gulp.task('clean:dist', function() { 
  return del.sync(['dist/**/*', '!dist/images', '!dist/images/**/*']); 
}); 
 
// Build Sequences 
// --------------- 
 
gulp.task('default', function(callback) { 
  runSequence(['sass', 'browserSync'], 'watch', 
    callback 
  ) 
}) 
 
gulp.task('build', function(callback) { 
  runSequence( 
    'clean:dist', 
    'sass', 
    ['useref', 'images', 'fonts'], 
    callback 
  ) 
})