Gulp：任务从未定义：任务

Question

我试图弄清楚如何使用 Gulp，但我不断收到一个错误，我不知道如何解决

当我使用它们的函数编译我的 SCSS 和 JS 文件时，它会正常编译但是当我尝试设置javascript gulp.task('watch')或javascript gulp.task('default')出现错误消息时

这是我的 gulpfile.js

const gulp = require('gulp');
const babel = require('gulp-babel');
const cssnano = require('gulp-cssnano');
const sass = require('gulp-sass');
const concat = require('gulp-concat');
const uglify = require('gulp-uglify');

const myFiles = [
    './app/js/vendors/*.js',
    './app/js/functions.js',
    './app/js/view.js'
]


gulp.task('sass', function () {
    return gulp.src('./app/style.scss')
        .pipe(sass())
        .pipe(cssnano())
        .pipe(gulp.dest('./dist/css'))
})


gulp.task('js', function () {
    return gulp.src(myFiles)
        .pipe(babel({
            presets: ['@babel/env']
        }))
        .pipe(concat('all.js'))
        .pipe(uglify())
        .pipe(gulp.dest('dist'));
})


gulp.task('watch', function () {
    gulp.watch('./app/*.scss', ['sass']);
    gulp.watch('./app/js/**/*.js', ['js']);
});


gulp.task('default', ['sass', 'js', 'watch']);

这是我发送时收到的错误 $ gulp default

assert.js:339
    throw err;
    ^

AssertionError [ERR_ASSERTION]: Task function must be specified
    at Gulp.set [as _setTask] (C:\Program Files (x86)\Ampps\www\gulp\node_modules\undertaker\lib\set-task.js:10:3)
    at Gulp.task (C:\Program Files (x86)\Ampps\www\gulp\node_modules\undertaker\lib\task.js:13:8)
    at Object.<anonymous> (C:\Program Files (x86)\Ampps\www\gulp\gulpfile.js:40:6)
    at Module._compile (internal/modules/cjs/loader.js:776:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)
    at Module.require (internal/modules/cjs/loader.js:690:17)
    at require (internal/modules/cjs/helpers.js:25:18)

如果我删除该功能default并尝试$ gulp watch

[10:19:14] Using gulpfile C:\Program Files (x86)\Ampps\www\gulp\gulpfile.js
[10:19:14] Starting 'watch'...
[10:19:14] 'watch' errored after 3.4 ms
[10:19:14] Error: watching ./app/*.scss: watch task has to be a function (optionally generated by using gulp.parallel or gulp.series)
    at Gulp.watch (C:\Program Files (x86)\Ampps\www\gulp\node_modules\gulp\index.js:31:11)
    at C:\Program Files (x86)\Ampps\www\gulp\gulpfile.js:35:10
    at taskWrapper (C:\Program Files (x86)\Ampps\www\gulp\node_modules\undertaker\lib\set-task.js:13:15)
    at bound (domain.js:402:14)
    at runBound (domain.js:415:12)
    at asyncRunner (C:\Program Files (x86)\Ampps\www\gulp\node_modules\async-done\index.js:55:18)
    at process._tickCallback (internal/process/next_tick.js:61:11)

编辑：按照下面的建议，我改变了我的 gulpfile.js 但现在我得到了一个不同的错误

gulp.task('watch', function () {
    gulp.watch('./app/*.scss', 'sass');
    gulp.watch('./app/js/**/*.js', 'js');
});

gulp.task('default', gulp.series('sass', 'js', 'watch'));

错误：

$ gulp default
[13:55:37] Using gulpfile C:\Program Files (x86)\Ampps\www\gulp\gulpfile.js
[13:55:37] Starting 'default'...
[13:55:37] Starting 'sass'...
[13:55:37] Finished 'sass' after 153 ms
[13:55:37] Starting 'js'...
[13:55:40] Finished 'js' after 2.49 s
[13:55:40] Starting 'watch'...
[13:55:40] 'watch' errored after 1.84 ms
[13:55:40] Error: watching ./app/*.scss: watch task has to be a function (optionally generated by using gulp.parallel or gulp.series)
    at Gulp.watch (C:\Program Files (x86)\Ampps\www\gulp\node_modules\gulp\index.js:31:11)
    at C:\Program Files (x86)\Ampps\www\gulp\gulpfile.js:40:10
    at taskWrapper (C:\Program Files (x86)\Ampps\www\gulp\node_modules\undertaker\lib\set-task.js:13:15)
    at bound (domain.js:402:14)
    at runBound (domain.js:415:12)
    at asyncRunner (C:\Program Files (x86)\Ampps\www\gulp\node_modules\async-done\index.js:55:18)
    at process._tickCallback (internal/process/next_tick.js:61:11)
[13:55:40] 'default' errored after 2.65 s

Answer 1

这些是 gulp v3 语法：

gulp.task('watch', function () {
    gulp.watch('./app/*.scss', ['sass']);
    gulp.watch('./app/js/**/*.js', ['js']);
});

gulp.task('default', ['sass', 'js', 'watch']);

如果您使用的是 gulp v4，请改用：

gulp.task('watch', function () {
    gulp.watch('./app/*.scss', gulp.series('sass'));
    gulp.watch('./app/js/**/*.js', gulp.series('js'));
});

gulp.task('default', gulp.series('sass', 'js', 'watch'));

并搜索如何从 gulp3 迁移到 gulp4。