text: const gulp = require('gulp');
  const gulp$babel = require('gulp-babel'),
      gulp$concat = require('gulp-concat'),
      gulp$eslint = require('gulp-eslint'),
      gulp$rimraf = require('gulp-rimraf'),
      gulp$sourcemaps = require('gulp-sourcemaps'),
      gulp$strip = require('gulp-strip-debug'),
      gulp$uglify = require('gulp-uglify'),
      gulp$util = require('gulp-util');
  
  const ARGS_OUTPUTFILES = gulp$util.env.outputFiles || 'both'; // 指示输出文件类型。可取值 both / min
  
  gulp.task('clean', () => {
      return gulp
          .src(['dist/**/*.js', 'dist/**/*.js.map'], {
              read: false
          })
          .pipe(
              gulp$rimraf({
                  force: true
              })
          );
  });
  
  gulp.task('eslint', () => {
      return gulp.src(['src/**/*.js']).pipe(gulp$eslint()).pipe(gulp$eslint.format()).pipe(gulp$eslint.failAfterError());
  });
  
  gulp.task(
      'dist',
      gulp.series('clean', () => {
          const files = ['src/**/*.js'];
          const babelOptions = {
              presets: [
                  [
                      '@babel/preset-env',
                      {
                          modules: false
                      }
                  ]
              ]
          };
  
          if ('both' === ARGS_OUTPUTFILES) {
              gulp.src(files)
                  .pipe(gulp$concat('index.js'))
                  .pipe(gulp$sourcemaps.init())
                  .pipe(gulp$babel(babelOptions))
                  .pipe(gulp$sourcemaps.write('.'))
                  .pipe(gulp.dest('dist'));
          }
  
          return gulp
              .src(files)
              .pipe(gulp$concat('index.min.js'))
              .pipe(gulp$strip())
              .pipe(gulp$sourcemaps.init())
              .pipe(gulp$babel(babelOptions))
              .pipe(gulp$uglify())
              .pipe(gulp$sourcemaps.write('.'))
              .pipe(gulp.dest('dist'));
      })
  );
  
  gulp.task('default', gulp.series('clean', 'eslint', 'dist'));
  