Everytime I run gulp anything, I get a assertion e

Question

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": "[e-mail]"
    },
    "author": "Css Ninja <[e-mail]> (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']);

Answer 1

Steps:

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

Answer 2

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

"gulp": "^3.9.1",