Gulp browserify, babelify, uglify and concat vendor files

gulpfile.js

/*! gulpfile.js */

const gulp = require("gulp");
const gutil = require("gulp-util");
const browserify = require("browserify");
const buffer = require("vinyl-buffer");
const uglify = require("gulp-uglify");
const sourcemaps = require("gulp-sourcemaps");
const source = require("vinyl-source-stream");
const concat = require("gulp-concat")

gulp.task("browserify", function() {
    const b = browserify({
        entries: "./src/app.js",
        debug: true,
    });

    return b
    .transform("babelify", {presets: ["es2015"]})
    .bundle()
    .pipe(source("app.js"))
    .pipe(buffer())
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(uglify())
    .on("error", gutil.log)
    .pipe(sourcemaps.write("./"))
    .pipe(gulp.dest("./dist/"));
});

gulp.task("bundle", ["browserify"], function() {
    return gulp.src([
        "vendor/jquery-3.1.0.min.js",
        "dist/app.js"
    ])
    .pipe(buffer())
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(concat("app.js"))
    .pipe(sourcemaps.write("./"))
    .pipe(gulp.dest("dist"));
});

Since gulp upgraded to version 4 you can't no more write :

gulp.task("bundle", ["browserify"], function() {
    return gulp.src([
        "vendor/jquery-3.1.0.min.js",
        "dist/app.js"
    ])
    .pipe(buffer())
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(concat("app.js"))
    .pipe(sourcemaps.write("./"))
    .pipe(gulp.dest("dist"));
});

You must correct this by

gulp.task("bundle", gulp.series("browserify", function() {
    return gulp.src([
        "vendor/jquery-3.1.0.min.js",
        "dist/app.js"
    ])
    .pipe(buffer())
    .pipe(sourcemaps.init({loadMaps: true}))
    .pipe(concat("app.js"))
    .pipe(sourcemaps.write("./"))
    .pipe(gulp.dest("dist"));
}));

Source : https://www.liquidlight.co.uk/blog/how-do-i-update-to-gulp-4/