Gulp: AssertionError [ERR_ASSERTION]: Task function must be specified

[jessehouwing]

Installed product versions

• Visual Studio: 2019 enterprise
• This extension: 2.8.396 & 3.2.447

Description

I used the "Convert to Gulp" option. The gulp file generated isn't compatible with the version of Gulp being installed by the extension.

Steps to recreate

1. take an existing bundleconfig.json
2. open the context menu and convert to gulp
3. gulp@latest is installed
4. The gulp file won't run

Current behavior

The gulp file seems to be meant to use gulp@^3.

AssertionError [ERR_ASSERTION]: Task function must be specified
    at Gulp.set [as _setTask] (C:\TFS\houwingj\**\node_modules\undertaker\lib\set-task.js:10:3)
    at Gulp.task (C:\TFS\houwingj\**\node_modules\undertaker\lib\task.js:13:8)
    at Object.<anonymous> (C:\TFS\houwingj\Cumulus\Dev03\Base2\Generic\Portal.Web\gulpfile.js:18:6)
    at Module._compile (internal/modules/cjs/loader.js:1138:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1158:10)
    at Module.load (internal/modules/cjs/loader.js:986:32)
    at Function.Module._load (internal/modules/cjs/loader.js:879:14)
    at Module.require (internal/modules/cjs/loader.js:1026:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at requireOrImport (C:\Users\reed\AppData\Roaming\npm\node_modules\gulp\node_modules\gulp-cli\lib\shared\require-or-import.js:19:11) {
  generatedMessage: false,
  code: 'ERR_ASSERTION',
  actual: false,
  expected: true,
  operator: '=='
}

Expected behavior

Either:

1. The right version of gulp is loaded.
2. Or the gulp file works with gulp 4.

See also: https://codeburst.io/switching-to-gulp-4-0-271ae63530c0

[jessehouwing]

This seems to do the trick, though it's still far from the ideal syntax:

"use strict";

var gulp = require("gulp"),
    concat = require("gulp-concat"),
    cssmin = require("gulp-cssmin"),
    htmlmin = require("gulp-htmlmin"),
    merge = require("merge-stream"),
    del = require("del"),
    bundleconfig = require("./bundleconfig.json"),
    sourcemaps = require("gulp-sourcemaps"),
    uglifyes = require('uglify-es'),
    composer = require('gulp-uglify/composer'),
    uglify = composer(uglifyes, console);

var regex = {
    css: /\.css$/,
    html: /\.(html|htm)$/,
    js: /\.js$/
};

function getBundles(regexPattern) {
    return bundleconfig.filter(function (bundle) {
        return regexPattern.test(bundle.outputFileName);
    });
}


gulp.task("minjs", gulp.series(async function () {
    var tasks = getBundles(regex.js).map(function (bundle) {
        return gulp.src(bundle.inputFiles, { base: "." })
            .pipe(sourcemaps.init())
            .pipe(concat(bundle.outputFileName))
            .pipe(uglify())
            .pipe(sourcemaps.write('.'))
            .pipe(gulp.dest("."));
    });
    merge(tasks);
}));

gulp.task("mincss", gulp.series(async function () {
    var tasks = getBundles(regex.css).map(function (bundle) {
        return gulp.src(bundle.inputFiles, { base: "." })
            .pipe(concat(bundle.outputFileName))
            .pipe(cssmin())
            .pipe(gulp.dest("."));
    });
    merge(tasks);
}));

gulp.task("min", gulp.series("minjs", "mincss"));

gulp.task("clean", gulp.series(async function () {
    var files = bundleconfig.map(function (bundle) {
        return bundle.outputFileName;
    });

    del(files);
}));

gulp.task("watch", gulp.series(async function () {
    getBundles(regex.js).forEach(function (bundle) {
        gulp.watch(bundle.inputFiles, gulp.series("minjs"));
    });

    getBundles(regex.css).forEach(function (bundle) {
        gulp.watch(bundle.inputFiles, gulp.series("mincss"));
    });
}));