CODEWITHSUNDEEP
gulpgulp-watch
Arthur Truong
Arthur Truong

Reputation: 2124

Everytime I run gulp anything, I get a assertion error. - Task function must be specified

I'm trying to run the command below but unfortunately I run into errors. 

$ gulp build

In my terminal and I get this assertion error. I've uninstalled node and NPM and reinstalled again using brew - How do I completely uninstall Node.js, and reinstall from beginning (Mac OS X) with these steps. My node version is v10.5.0 and npm version is 6.1.0.

My system is MacOS High Sierra 10.13.2 

assert.js:269
    throw err;
    ^

AssertionError [ERR_ASSERTION]: Task function must be specified
    at Gulp.set [as _setTask] (bulkit/startup-kit/node_modules/undertaker/lib/set-task.js:10:3)
    at Gulp.task (startup-kit/node_modules/undertaker/lib/task.js:13:8)
    at Object.<anonymous> 
    at Module._compile (internal/modules/cjs/loader.js:702:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:713:10)
    at Module.load (internal/modules/cjs/loader.js:612:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:551:12)
    at Function.Module._load (internal/modules/cjs/loader.js:543:3)
    at Module.require (internal/modules/cjs/loader.js:650:17)
    at require (internal/modules/cjs/helpers.js:20:18)

package.json

{
    "name": "bulkit-startup",
    "version": "0.0.1",
    "description": "Bulkit Startup Kit",
    "main": "Gruntfile.js",
    "devDependencies": {
        "autoprefixer": "^6.3.6",
        "browser-sync": "^2.24.5",
        "gulp": "^4.0.0",
        "gulp-clean": "^0.3.2",
        "gulp-concat": "^2.6.0",
        "gulp-postcss": "^6.1.0",
        "gulp-sass": "^2.2.0",
        "gulp-sourcemaps": "^1.6.0",
        "jquery": "^3.3.1",
        "mq4-hover-shim": "^0.3.0",
        "panini": "^1.3.0",
        "rimraf": "^2.5.2"
    },
    "engines": {
        "node": ">=0.10.1"
    },
    "scripts": {
        "start": "gulp",
        "build": "gulp build"
    },
    "repository": {
        "type": "git",
        "url": "https://github.com/cssninjaStudio/bulkit.git"
    },
    "bugs": {
        "url": "https://github.com/cssninjaStudio/bulkit/issues",
        "email": "[email protected]"
    },
    "author": "Css Ninja <[email protected]> (https://cssninja.io/themes/bulkit)",
    "license": "Commercial",
    "private": true,
    "dependencies": {
        "bulma": "^0.7.0",
        "del": "^3.0.0",
        "jquery-waypoints": "^2.0.5",
        "jquery.counterup": "^2.1.0",
        "scrollreveal": "^3.4.0",
        "slick-carousel": "^1.8.1",
        "wallop": "^2.4.1"
    }
}

gulpfile.js

var gulp = require('gulp');
var clean = require('gulp-clean');
var sass = require('gulp-sass');
var sourcemaps = require('gulp-sourcemaps');
var postcss = require('gulp-postcss');
var autoprefixer = require('autoprefixer');
var mq4HoverShim = require('mq4-hover-shim');
var rimraf = require('rimraf').sync;
var browser = require('browser-sync');
var panini = require('panini');
var concat = require('gulp-concat');
var port = process.env.SERVER_PORT || 8080;
var nodepath =  'node_modules/';
var assetspath =  'assets/';

// Starts a BrowerSync instance
gulp.task('server', ['build'], function(){
    browser.init({server: './_site', port: port});
});

// Watch files for changes
gulp.task('watch', function() {
    gulp.watch('scss/**/*', ['compile-scss', browser.reload]);
    gulp.watch('sass/**/*', ['compile-sass', browser.reload]);
    gulp.watch('js/**/*', ['copy-js', browser.reload]);
    gulp.watch('images/**/*', ['copy-images', browser.reload]);
    gulp.watch('html/pages/**/*', ['compile-html']);
    gulp.watch(['html/{layouts,includes,helpers,data}/**/*'], ['compile-html:reset','compile-html']);
    gulp.watch(['./src/{layouts,partials,helpers,data}/**/*'], [panini.refresh]);
});

// Erases the dist folder
gulp.task('reset', function() {
    rimraf('bulma/*');
    rimraf('scss/*');
    rimraf('assets/css/*');
    rimraf('assets/fonts/*');
    rimraf('images/*');
});

// Erases the dist folder
gulp.task('clean', function() {
    rimraf('_site');
});

// Copy Bulma filed into Bulma development folder
gulp.task('setupBulma', function() {
    //Get Bulma from node modules
    gulp.src([nodepath + 'bulma/*.sass']).pipe(gulp.dest('bulma/'));
    gulp.src([nodepath + 'bulma/**/*.sass']).pipe(gulp.dest('bulma/'));
});

// Copy static assets
gulp.task('copy', function() {
    //Copy other external font and data assets
    gulp.src(['assets/fonts/**/*']).pipe(gulp.dest('_site/assets/fonts/'));
    gulp.src([nodepath + 'slick-carousel/slick/fonts/**/*']).pipe(gulp.dest('_site/assets/css/fonts/'));
    gulp.src([nodepath + 'slick-carousel/slick/ajax-loader.gif']).pipe(gulp.dest('_site/assets/css/'));
});

//Theme Sass variables
var sassOptions = {
    errLogToConsole: true,
    outputStyle: 'compressed',
    includePaths: [nodepath + 'bulma/sass']
};

//Theme Scss variables
var scssOptions = {
    errLogToConsole: true,
    outputStyle: 'compressed',
    includePaths: ['./scss/partials']
};

// Compile Bulma Sass
gulp.task('compile-sass', function () {
    var processors = [
        mq4HoverShim.postprocessorFor({ hoverSelectorPrefix: '.is-true-hover ' }),
        autoprefixer({
            browsers: [
                "Chrome >= 45",
                "Firefox ESR",
                "Edge >= 12",
                "Explorer >= 10",
                "iOS >= 9",
                "Safari >= 9",
                "Android >= 4.4",
                "Opera >= 30"
            ]
        })//,
        //cssnano(),
    ];
    //Watch me get Sassy
    return gulp.src('./bulma/bulma.sass')
        .pipe(sourcemaps.init())
        .pipe(sass(sassOptions).on('error', sass.logError))
        .pipe(postcss(processors))
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('./_site/assets/css/'));
});

// Compile Theme Scss
gulp.task('compile-scss', function () {
    var processors = [
        mq4HoverShim.postprocessorFor({ hoverSelectorPrefix: '.is-true-hover ' }),
        autoprefixer({
            browsers: [
                "Chrome >= 45",
                "Firefox ESR",
                "Edge >= 12",
                "Explorer >= 10",
                "iOS >= 9",
                "Safari >= 9",
                "Android >= 4.4",
                "Opera >= 30"
            ]
        })//,
        //cssnano(),
    ];
    //Watch me get Sassy
    return gulp.src('./scss/core.scss')
        .pipe(sourcemaps.init())
        .pipe(sass(sassOptions).on('error', sass.logError))
        .pipe(postcss(processors))
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('./_site/assets/css/'));
});

// Compile Html
gulp.task('compile-html', function() {
    gulp.src('html/pages/**/*.html')
        .pipe(panini({
        root: 'html/pages/',
        layouts: 'html/layouts/',
        partials: 'html/includes/',
        helpers: 'html/helpers/',
        data: 'html/data/'
    }))
        .pipe(gulp.dest('_site'))
        .on('finish', browser.reload);
});

gulp.task('compile-html:reset', function(done) {
    panini.refresh();
    done();
});

// Compile css from node modules
gulp.task('compile-css', function() {
    return gulp.src([ 
        nodepath + 'slick-carousel/slick/slick.css',
        nodepath + 'slick-carousel/slick/slick-theme.css',
        nodepath + 'wallop/css/wallop.css',
        //Additional static css assets
        assetspath + 'css/icons.min.css',
    ])
        .pipe(concat('app.css'))
        .pipe(gulp.dest('./_site/assets/css/'));
});

// Compile js from node modules
gulp.task('compile-js', function() {
    return gulp.src([ 
        nodepath + 'jquery/dist/jquery.min.js', 
        nodepath + 'slick-carousel/slick/slick.min.js', 
        nodepath + 'scrollreveal/dist/scrollreveal.min.js',
        nodepath + 'waypoints/lib/jquery.waypoints.min.js',
        nodepath + 'waypoints/lib/shortcuts/sticky.min.js',
        nodepath + 'jquery.counterup/jquery.counterup.min.js',
        nodepath + 'wallop/js/Wallop.min.js',
        //Additional static js assets
        assetspath + 'js/ggpopover/ggpopover.min.js',
        assetspath + 'js/ggpopover/ggtooltip.js',
        assetspath + 'js/embed/embed.js',
        assetspath + 'js/gmap/gmap.min.js',
    ])
        .pipe(concat('app.js'))
        .pipe(gulp.dest('./_site/assets/js/'));
});

//Copy Theme js to production site
gulp.task('copy-js', function() {
    gulp.src('js/**/*.js')
        .pipe(gulp.dest('./_site/assets/js/'));
});

//Copy images to production site
gulp.task('copy-images', function() {
    gulp.src('images/**/*')
        .pipe(gulp.dest('./_site/assets/images/'));
});

gulp.task('init', ['setupBulma']);
gulp.task('build', ['clean','copy', 'compile-js', 'compile-css', 'copy-js', 'compile-sass', 'compile-scss', 'compile-html', 'copy-images']);
gulp.task('default', ['server', 'watch']);

Upvotes: 185

Views: 190064

Answers (13)

user19058992
user19058992

Reputation:

Replace the array in:

gulp.task('default', ['task1', 'task2','task3']);

with gulp.series()

gulp.task('default', gulp.series('task1', 'task2','task3'));

Upvotes: 7

Deepak Rajpal
Deepak Rajpal

Reputation: 1011

While migrating from Gulp 3.x to Gulp 4.x, these are the common errors we are getting:

Errors:

  • AssertionError [ERR_ASSERTION]: Task function must be specified
  • AssertionError [ERR_ASSERTION]: Task never defined:
  • The following tasks did not complete: Did you forget to signal async completion?

Here are few points to take care regarding task definition and execution:

  1. First define task
  2. Use return
  3. Then execute with gulp.series()

Here, is the quick Gulp code which is working with Gulp v4:

// First define task with Return
gulp.task('css-minify', function () {
    return gulp.src('assets/images/*.*')
        .pipe(smushit({verbose: true}))
        .pipe(gulp.dest('assets/images'));
});

// Then execute task with bracket '()' instead of '[]'
gulp.task('default', gulp.series('css-minify'));

Upvotes: 7

Machavaram Akhil pavan sai
Machavaram Akhil pavan sai

Reputation: 1

worked after updating gulp.task() with gulp.task( gulp.series() );

Upvotes: 0

Augusto Principe
Augusto Principe

Reputation: 29

Replacing [] with gulp.series() definitely worked to me, and another change I've needed to do was to move my main task 'Ex. gulp main-task' to the end of the Gulp file using Gulp v4.02

Upvotes: 1

Anushil Kumar
Anushil Kumar

Reputation: 672

The problem is that you are using gulp 4 and the syntax in gulfile.js is of gulp 3. So either downgrade your gulp to 3.x.x or make use of gulp 4 syntaxes.

Syntax Gulp 3:

gulp.task('default', ['sass'], function() {....} );

Syntax Gulp 4:

gulp.task('default', gulp.series(sass), function() {....} );

You can read more about gulp and gulp tasks on: https://medium.com/@sudoanushil/how-to-write-gulp-tasks-ce1b1b7a7e81

Upvotes: 11

Sadee
Sadee

Reputation: 3170

It's not good to keep changing the gulp & npm versions in-order to fix the errors. I was getting several exceptions last days after reinstall my working machine. And wasted tons of minutes to re-install & fixing those.

So, I decided to upgrade all to latest versions: 

npm -v : v12.13.0 
node -v : 6.13.0
gulp -v : CLI version: 2.2.0 Local version: 4.0.2

This error is getting because of the how it has coded in you gulpfile but not the version mismatch. So, Here you have to change 2 things in the gulpfile to aligned with Gulp version 4. Gulp 4 has changed how initiate the task than Version 3.

  1. In version 4, you have to defined the task as a function, before call it as a gulp task by it's string name. In V3:

gulp.task('serve', ['sass'], function() {..});

But in V4 it should be like:

function serve() {
...
}
gulp.task('serve', gulp.series(sass));
  1. As @Arthur has mentioned, you need to change the way of passing arguments to the task function. It was like this in V3:

gulp.task('serve', ['sass'], function() { ... });

But in V4, it should be: 

gulp.task('serve', gulp.series(sass));

Upvotes: 4

Arif I.
Arif I.

Reputation: 2192

Try replacing your last line of gulpfile.js

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

with

gulp.task('default', gulp.series('server', 'watch'));

Upvotes: 127

Dann
Dann

Reputation: 1

Steps:

  1. "gulp": "^3.9.1",
  2. npm install
  3. gulp styles

Upvotes: -8

Motahar Hossain
Motahar Hossain

Reputation: 563

You don't need to downgrade your gulp from gulp 4. Use gulp.series() to combine multiple tasks. At first install gulp globally with

npm install --global gulp-cli

and then install locally on your working directory with

npm install --save-dev gulp

see details here

Example:

package.json

{
  "name": "gulp-test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "browser-sync": "^2.26.3",
    "gulp": "^4.0.0",
    "gulp-sass": "^4.0.2"
  },
  "dependencies": {
    "bootstrap": "^4.3.1",
    "jquery": "^3.3.1",
    "popper.js": "^1.14.7"
  }
}

gulpfile.js

var gulp = require("gulp");
var sass = require('gulp-sass');
var browserSync = require('browser-sync').create();

// Specific Task
function js() {
    return gulp
    .src(['node_modules/bootstrap/dist/js/bootstrap.min.js', 'node_modules/jquery/dist/jquery.min.js', 'node_modules/popper.js/dist/umd/popper.min.js'])
    .pipe(gulp.dest('src/js'))
    .pipe(browserSync.stream());
}
gulp.task(js);

// Specific Task
function gulpSass() {
    return gulp
    .src(['src/scss/*.scss'])
    .pipe(sass())
    .pipe(gulp.dest('src/css'))
    .pipe(browserSync.stream());
}
gulp.task(gulpSass);

// Run multiple tasks
gulp.task('start', gulp.series(js, gulpSass));

Run gulp start to fire multiple tasks & run gulp js or gulp gulpSass for specific task.

Upvotes: 21

standevenjw
standevenjw

Reputation: 2714

Gulp 4.0 has changed the way that tasks should be defined if the task depends on another task to execute. The list parameter has been deprecated.

An example from your gulpfile.js would be:

// Starts a BrowerSync instance
gulp.task('server', ['build'], function(){
  browser.init({server: './_site', port: port});
});

Instead of the list parameter they have introduced gulp.series() and gulp.parallel().

This task should be changed to something like this:

// Starts a BrowerSync instance
gulp.task('server', gulp.series('build', function(){
  browser.init({server: './_site', port: port});
}));

I'm not an expert in this. You can see a more robust example in the gulp documentation for running tasks in series or these following excellent blog posts by Jhey Thompkins and Stefan Baumgartner

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

https://fettblog.eu/gulp-4-parallel-and-series/

Upvotes: 269

Ashim Sth
Ashim Sth

Reputation: 131

https://fettblog.eu/gulp-4-parallel-and-series/

Because gulp.task(name, deps, func) was replaced by gulp.task(name, gulp.{series|parallel}(deps, func)).

You are using the latest version of gulp but older code. Modify the code or downgrade.

Upvotes: 12

Jopie
Jopie

Reputation: 332

I get the same error when using Gulp. The solution is to switch to Gulp version 3.9.1, both for the local version and the CLI version.

sudo npm install -g [email protected]

Run in the project's folder

npm install [email protected]

Upvotes: 10

Samyak Jain
Samyak Jain

Reputation: 922

Lower your gulp version in package.json file to 3.9.1- 

"gulp": "^3.9.1",

Upvotes: 25

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