Gulp Error Task '+name+' requires a function that is a function

Question

A similar question has been asked previously here:

Error: Task requires a name at Gulp.Orchestrator.add

In my case I was setting up a gulp build.

Installed

gulp-connect
gulp-postcss
gulp-sourcemaps

when I run gulp I get

Error

    C:\Users\jwilson\Documents\James\jameswilson.co.za\node_modules\orchestrator\index.js:44
                            throw new Error('Task '+name+' requires a function that is a function');
                            ^

Error: Task default requires a function that is a function
    at Gulp.Orchestrator.add (C:\Users\jwilson\Documents\James\jameswilson.co.za\node_modules\orchestrator\index.js:44:10)
    at Object.<anonymous> (C:\Users\jwilson\Documents\James\jameswilson.co.za\gulpfile.js:19:6)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Liftoff.handleArguments (C:\Users\jwilson\AppData\Roaming\npm\node_modules\gulp\bin\gulp.js:116:3)

Gulpfile

var gulp = require('gulp'),
  connect = require('gulp-connect');
  postcss = require('gulp-postcss');
  sourcemaps = require('gulp-sourcemaps');

gulp.task('connect', function() {
  connect.server();
});

gulp.task('css', function () {

  return gulp.src('src/**/*.css')
      .pipe( sourcemaps.init() )
      .pipe( postcss([ require('precss'), require('autoprefixer') ]) )
      .pipe( sourcemaps.write('.') )
      .pipe( gulp.dest('build/') );
});

gulp.task('default', ['css'], ['connect']);

Answer 1

I think the error is here:

gulp.task('default', ['css'], ['connect']);

It looks to me as if you are using gulp v3.9.1 or older. In this case, gulp.task takes up to three arguments: a task name, an array of dependent task names, and a function. You are passing a task name and two 1-element arrays. Gulp is complaining because it was expecting the third argument to task to be a function but you passed it the array ['connect'].

I imagine you want to replace the two 1-element arrays with a 2-element array:

gulp.task('default', ['css', 'connect']);

---

For gulp v4 or later, you can run the two tasks in series using the following:

gulp.task('default', gulp.series('css', 'connect'));

Or in parallel, using:

gulp.task('default', gulp.parallel('css', 'connect'));