documentation in readme

README.md

@@ -11,13 +11,91 @@ This package aims to help gulp tasks coded in gulp 3 syntax run in gulp 4.
 ### Use
 
 ```javascript
+const gulp = require('gulp');
 const runSequence = require('gulp4-run-sequence');
+const fs = require('fs');
+
+// This will run in this order:
+// * boil-water
+// * steep-tea and boil-egg in parallel
+// * peel-egg
+// * Finally call the callback function
+gulp.task('build', function (callback) {
+  runSequence(
+    'boil-water',
+    ['steep-tea', 'boil-egg'],
+    'peel-egg',
+    callback
+//  ^^^^^^^^
+//  This informs that the sequence is complete.
+  );
+});
+
+// Configure boil-water, steep-tea, boil-egg, and peel-egg as you wish,
+// but make sure they return a stream or promise, or handle the callback.
+// Example:
+
+gulp.task('boil-water', function() {
+  // Return the stream from gulp.
+  return gulp.src(water).pipe(...)...
+});
+
+gulp.task('boil-egg', function() {
+  return new Promise(function (resolve, reject) {
+    // Make sure asynchronous tasks are resolved or rejected.
+  });
+});
+
+gulp.task('peel-egg', function(callback) {
+  fs.readFile('egg', function (err, data) {
+    // Consume data...
+    callback();
+//  ^^^^^^^^
+//  This informs that the task is complete.
+  });
+});
+```
+
+### Use within gulp submodules
+
+If you have a complex gulp setup with your tasks split up across different 
+files, you may get the error that `gulp4-run-sequence` is unable to find your 
+tasks. In this case, you can configure `gulp4-run-sequence` to look at the gulp 
+within the submodule, like so:
+
+```javascript
+// Explicitly declare gulp particular to your submodule.
+const gulp = require('gulp');
+// Explicitly assign this gulp to gulp4-run-sequence.
+const runSequence = require('gulp4-run-sequence').use(gulp);
+
+// ...and then use normally.
+gulp.task('supertask', function (callback) {
+  runSequence('subtask0', 'subtask1', callback);
+});
 ```
 
-See the gulp 3 [run-sequence docs](https://github.com/OverZealous/run-sequence) 
-for further documentation on usage.
+### Options
+
+The options in the gulp 3 version of run-sequence no longer apply. 
+
+`showErrorStackTrace` no longer applies because errors are handled entirely 
+within the gulp4 stack. A good command of streams, promises, and callback 
+functions will deliver the desired amount of error verbosity.
+
+`ignoreUndefinedTasks` no longer applies because all falsey arguments will be 
+skipped without a warning. The logic follows the best practice of looking for 
+positives, rather than looking for a subset of the infinite set of negatives, in 
+order to warn that there's a negative, only to skip it or exit on it.
+
+### Acknowledgements
+
+This package is inspired entirely by 
+[run-sequence](https://github.com/OverZealous/run-sequence) for gulp 3. Credit 
+and gratitude are due for 
+[its contributors](https://github.com/OverZealous/run-sequence/graphs/contributors). 
 
-Also recommended: [gulp 3 with long-term support](https://github.com/electric-eloquence/gulp)
+#### Also recommended: [gulp 3 with long-term support](https://github.com/electric-eloquence/gulp)
 
 [snyk-image]: https://snyk.io/test/github/electric-eloquence/gulp4-run-sequence/master/badge.svg
 [snyk-url]: https://snyk.io/test/github/electric-eloquence/gulp4-run-sequence/master

index.js

@@ -41,3 +41,4 @@ module.exports = runSequence.bind(null, null);
 module.exports.use = function (gulp) {
   return runSequence.bind(null, gulp);
 };
+module.exports.options = {};