问未在gulp中定义的对象

EN

var gulp        = require('gulp');
var browserSync = require('browser-sync');
var sass        = require('gulp-sass');
var prefix      = require('gulp-autoprefixer');
var cp          = require('child_process');
var pug         = require('gulp-pug');

var jekyll   = process.platform === 'win32' ? 'jekyll.bat' : 'jekyll';
var messages = {
    jekyllBuild: '<span style="color: grey">Running:</span> $ jekyll build'
};

/**
 * Build the Jekyll Site
 */
gulp.task('jekyll-build', function (done) {
    browserSync.notify(messages.jekyllBuild);
    return cp.spawn( jekyll , gulp.task('build'), {stdio: 'inherit'})
        .on('close', done);
});

/**
 * Rebuild Jekyll & do page reload
 */
gulp.task('jekyll-rebuild', gulp.task('jekyll-build'), function () {
    browserSync.reload();
});

/**
 * Wait for jekyll-build, then launch the Server
 */
gulp.task('browser-sync', gulp.series('sass', 'jekyll-build'), function() {
    browserSync({
        server: {
            baseDir: '_site'
        },
        notify: false
    });
});

/**
 * Compile files from _scss into both _site/css (for live injecting) and site (for future jekyll builds)
 */
gulp.task('sass', function () {
  return gulp.src('raw-assets/sass/**/*.scss')
    .pipe(sass().on('error', sass.logError))
    .pipe(autoprefixer(['last 15 versions', '> 1%', 'ie 8', 'ie 7'], { cascade: true }))
.    pipe(gulp.dest('assets/css'))
});

/**
* Compile files from _pugfiles into _includes (for live injecting) and site 
(for future jekyll builds)
*/
gulp.task('pug', function buildHTML() {
  return gulp.src('_pugfiles/*.pug')
  .pipe(pug({
    // Your options in here.
    pretty: true
  }))
  .pipe(gulp.dest('_includes'));
});

/**
 * Watch scss files for changes & recompile
 * Watch html/md files/pug files, run jekyll & reload BrowserSync
 */
gulp.task('watch', function () {
    gulp.watch('assets/css/**', gulp.task('sass'));
    gulp.watch(['*.html', '_layouts/*.html', '_includes/*'], gulp.task('jekyll-rebuild'));
    gulp.watch(['_pugfiles/*.pug'], gulp.task('pug'));
});

    /**
     * Default task, running just `gulp` will compile the sass,
     * compile the jekyll site, launch BrowserSync & watch files.
     */
    gulp.task('default', gulp.series('browser-sync', 'watch'));

gulp.task('', []) 

gulp.task('', gulp.series())