Make a beautiful class-based gulpfiles with Typescript and Gulpclass

Allows to create a gulp files in classes, each method of which can be a gulp task.

Installation

1. Install module:

npm install gulpclass --save-dev

2. Use typings to install all required definition dependencies.

typings install

Usage

1. Create a gulpfile.ts and describe your tasks

``javascript
import {Gulpclass, Task, SequenceTask} from "gulpclass";
import * as gulp from "gulp";
import * as del from "del";

@Gulpclass()
export class Gulpfile {

@Task() // return promise to indicate your task completion
clean() {
// del module returns promise for you automatically
return del("./dist/**");
}

@Task() // or use provided callback instead
clean(cb: Function) {
return del("./dist/**", cb);
}

@Task()
copyFiles() { // don't forget to return stream from your task function
return gulp.src(["./README.md"])
.pipe(gulp.dest("./dist"));
}

@Task("copy-source-files") // you can specify custom task name if you need
copySourceFiles() {
return gulp.src(["./src/**.js"])
.pipe(gulp.dest("./dist/src"));
}

@SequenceTask() // this special annotation using "run-sequence" module to run returned tasks in sequence
build() {
return ["copyFiles", "copy-source-files"];
}

// list of dependencies could be specified as a second argument to trigger other tasks
// the example below is equivalent to gulp.task("default", ["build"]);
@Task("default", ["build"])
defaultTask() {
// using "defaultTask", because "default" is a reserved keyword in ES2015
}

}
`

2. How to run

## First option. Use ts-node

Install ts-node, it supports running gulp tasks directly using gulp command


## Second option. If you don't want to use ts-node

There is a caveat of using gulp and typescript together. The problem is that when you run your gulp commands
in console, gulp cannot read your tasks from your typescript code - it can read only from gulpfile.js.
But there is a simple workaround - you can create a gulpfile.js, compile and execute typescript on-the-fly.

Create a gulpfile.js and put there this piece of code:
`javascript
eval(require("typescript").transpile(require("fs").readFileSync("./gulpfile.ts").toString()));
`
This piece of code reads your gulpfile.ts contents, and asks typescript to transpile it on-the-fly and executes transpiled result as javascript.

(you need to run npm install typescript --save-dev if you dont have typescript package installed)

Please note that if you are NOT using outDir in typescript compile options, you may have problems if your
gulpclass file is named gulpfile.ts typescript compiler will try to compile it to gulpfile.js, and will override
code you added to gulpfile.js. Solution is simple - rename your gulpfile.ts. You can call it as you wish,
for example you can call it gulpclass.ts.

## Alternative approaches

Alternative approaches depend on which tsconfig configuration you use. These examples assume that you are using
"outDir": "build" as a directory to where files are compiled:

* create gulpfile.js and put there `require("build/gulpfile")`
* or run gulp in cmd with extra parameters: gulp --gulpfile build/gulpfile.js --cwd .

Benefits of this apporach is that you can use debug your gulp classes in IDEs.

FAQ

* How to load tasks from multiple files?

Edit your gulpfile.js and change it following way:

`javascript
const files = [
"./othertask.ts",
"./gulpfile.ts"
];
files.forEach(function(file) { eval(require("typescript").transpile(require("fs").readFileSync(file).toString())) });
`

* How to use task dependencies?

Simple use second argument of the @Task decorator:

`javascript
@Task("someTask", ["clean", "compile"])
someTask() {
return doSomething();
}
`

* Why my task gulp.task("default", ["clean", "compile", "build"]) is not working?

I have such a task and its not working:

`javascript
@Task("default")
default() {
return ["clean", "compile", "build"];
}
`

Why? Because the array you are returning is what task is doing, not a task
dependencies as you wish:

`javascript
@Task("default", ["clean", "compile", "build"])
default() {
}
``

Samples

This project itself using gulpfile.ts.
Take a look on it as an example.