# Task Module

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This is a helper module for Minecraft Launcher. See the github home page for more information.

## Usage

### Progress Moniting

You can use `@xmcl/task` model to track the progress of a task. *In the launcher, they are majorly download task.*

This module implements a basic object model for task with progress. The task can be paused or cancelled.

```ts
    import { Task, TaskBase, task } from "@xmcl/task";

    class ATask extends TaskBase {
        // implement a task
    }

    class BTask extends TaskBase {
        // implement a task
    }

    // suppose you have such task
    const myTask = task("hello", function() {
        await this.yield(new ATask().setName("world"));
        await this.yield(new BTask().setName("xmcl"));
    });

    // start a task
    const result = await task.startAndWait({
        onStart(task: Task<any>) {
            // the task path is the task name joined by dot (.)
            const path = task.path;
            console.log(`${path} started!`);
        },
        onUpdate(task: Task<any>, chunkSize: number) {
            // a task update
        },
        onFailed(task: Task<any>, error: any) {
            // on a task fail
        },
        onSucceed(task: Task<any>, result: any) {
            // on task success
            const path = task.path;
            console.log(`${path} ended!`);
        },
        // on task is paused/resumed/cancelled
        onPaused(task: Task<any>) { },
        onResumed(task: Task<any>) { },
        onCancelled(task: Task<any>) { },
    });
    // the result will print like
    // hello started!
    // hello.world started!
    // hello.world ended!
    // hello.xmcl started!
    // hello.xmcl ended!
    // hello ended!
```