---
product: Chilkat
product_version: 11.7.0
language: js
language_label: JavaScript
class: TaskChain
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/jsTaskChainRef.html
---
# Chilkat TaskChain — JavaScript — v11.7.0

> Chilkat 11.7.0 · language=js · class=TaskChain
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/TaskChain.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/js/guide.md`.

## Purpose

**Run multiple asynchronous Chilkat tasks in a defined sequence.**

`Chilkat.TaskChain` manages a sequence of `Chilkat.Task` objects and runs them one after another. It is useful when multiple asynchronous Chilkat operations must execute in a predictable order while still allowing the entire chain to be started, monitored, waited on, canceled, or run synchronously. A task chain can stop when a task fails, or continue depending on the configured behavior.

**Sequential async workflow**

Append multiple `Task` objects and run them in order when one operation must finish before the next begins.

**Chain-level execution**

Start the entire chain, run it synchronously, wait for completion, or cancel the chain as a single coordinated operation.

**Monitor progress and status**

Inspect whether the chain is live, finished, inert, canceled, failed, or still running.

**Access individual tasks**

Retrieve tasks by index after execution to inspect each task's status, success flag, error text, and result.

**Stop-on-failure control**

Use `StopOnFailedTask` to control whether the chain stops at the first failed task or continues to later tasks.

**Diagnostics**

Use task and chain status information together with `LastErrorText` and each task's result details to troubleshoot ordered async workflows.

**Common pattern:** Create the individual async tasks, append them to a `TaskChain` in the required order, set `StopOnFailedTask` as appropriate, run the chain, wait for completion, then inspect each task's success status and result. Use `TaskChain` when operations must run sequentially; use individual `Task` objects when each async operation can be managed on its own.

For an extended overview, see [TaskChain Class Overview](https://www.chilkatsoft.com/taskchain_class_overview.asp).

## Object creation, unlocking and error handling

**Object Creation**

Note: This is intended for running within a [Chilkat.Js embedded JavaScript engine](https://www.chilkatsoft.com/chilkat_javascript_engine.asp).

```
var obj = new CkTaskChain();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in JavaScript.

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `DebugLogFilePath` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `LastErrorHtml` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `LastErrorText` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `LastErrorXml` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `LastMethodSuccess` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `VerboseLogging` | `VerboseLogging` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `Version` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `Finished` | property, read-only | `Finished` |
| `Inert` | property, read-only | `Inert` |
| `Live` | property, read-only | `Live` |
| `NumTasks` | property, read-only | `NumTasks` |
| `Status` | property, read-only | `Status` |
| `StatusInt` | property, read-only | `StatusInt` |
| `StopOnFailedTask` | property, read/write | `StopOnFailedTask` |
| `Append` | method | `var success = Append(task);` |
| `Cancel` | method | `var success = Cancel();` |
| `Run` | method | `var success = Run([taskCompleted]);` |
| `RunSynchronously` | method | `var success = RunSynchronously();` |
| `SleepMs` | method | `SleepMs(numMs);` |
| `Wait` | method | `var success = Wait(maxWaitMs);` |

## Properties

### TaskChain.Finished

`Chilkat 11.7.0 · js · TaskChain · Finished · property · read-only · since 9.5.0.52`

```javascript
Finished
```

· `boolean`, `read-only`

`true` if the task status is `canceled`, `aborted`, or `completed`. A task chain can only reach the `canceled` status if it was activated via the Run method, made it onto the internal thread pool thread's queue, was waiting for a pool thread to become available, and was then canceled prior to the task actually starting.

### TaskChain.Inert

`Chilkat 11.7.0 · js · TaskChain · Inert · property · read-only · since 9.5.0.52`

```javascript
Inert
```

· `boolean`, `read-only`

`true` if the task status is `empty` or `loaded`. When a task chain is inert, it has been loaded but is not scheduled to run yet.

### TaskChain.Live

`Chilkat 11.7.0 · js · TaskChain · Live · property · read-only · since 9.5.0.52`

```javascript
Live
```

· `boolean`, `read-only`

`true` if the task status is `queued` or `running`. When a task chain is live, it is either already running, or is on the thread pool thread's queue waiting for a thread to become available.

### TaskChain.NumTasks

`Chilkat 11.7.0 · js · TaskChain · NumTasks · property · read-only · since 9.5.0.52`

```javascript
NumTasks
```

· `int`, `read-only`

The number of tasks contained within the task chain.

### TaskChain.Status

`Chilkat 11.7.0 · js · TaskChain · Status · property · read-only · since 9.5.0.52`

```javascript
Status
```

· `string`, `read-only`

The current status of the task chain. Possible values are:

- `empty` -- No tasks have yet been appended to the task chain.
- `loaded` -- The task chain has been loaded (appended) with one or more task objects.
- `queued` -- The task chain is in the thread pool's queue of tasks awaiting to be run.
- `running` -- The task chain is currently running.
- `canceled` -- The task chain was canceled before it entered the `running` state.
- `aborted` -- The task chain was canceled while it was in the running state.
- `completed` -- The task chain completed.

### TaskChain.StatusInt

`Chilkat 11.7.0 · js · TaskChain · StatusInt · property · read-only · since 9.5.0.52`

```javascript
StatusInt
```

· `int`, `read-only`

The current status of the task as an integer value. Possible values are:

- **1** -- `empty` -- No tasks have yet been appended to the task chain.
- **2** -- `loaded` -- The task chain has been loaded (appended) with one or more task objects.
- **3** -- `queued` -- The task chain is in the thread pool's queue of tasks awaiting to be run.
- **4** -- `running` -- The task chain is currently running.
- **5** -- `canceled` -- The task chain was canceled before it entered the `running` state.
- **6** -- `aborted` -- The task chain was canceled while it was in the running state.
- **7** -- `completed` -- The task chain completed.

### TaskChain.StopOnFailedTask

`Chilkat 11.7.0 · js · TaskChain · StopOnFailedTask · property · read/write · since 9.5.0.52`

```javascript
StopOnFailedTask
```

· `boolean`

If `true` then stops execution of the task chain if any individual task fails. Task failure is defined by the standard LastMethodSuccess property. If `false`, then all of the tasks in the chain will be run even if some fail. The default value of this property is `true`.

## Methods

### TaskChain.Append

`Chilkat 11.7.0 · js · TaskChain · Append · method · since 9.5.0.52`

```javascript
var success = Append(task);
```

· return: `boolean`; `true` for success, `false` for failure  
· task: `CkTask`

Appends a task to the task chain. Can fail if the task is already part of another chain. (A task can only be part of a single chain.)

Returns true for success, false for failure.

### TaskChain.Cancel

`Chilkat 11.7.0 · js · TaskChain · Cancel · method · since 9.5.0.52`

```javascript
var success = Cancel();
```

· return: `boolean`; `true` for success, `false` for failure

Cancels execution of the asynchronous task chain.

Returns true for success, false for failure.

### TaskChain.Run

`Chilkat 11.7.0 · js · TaskChain · Run · method · since 9.5.0.52`

```javascript
var success = Run([taskCompleted]);
```

· return: `boolean`; `true` for success, `false` for failure

Queues the task chain to run on the internal Chilkat thread pool. Each task in the chain will run, one after the other.

Returns true for success, false for failure.

### TaskChain.RunSynchronously

`Chilkat 11.7.0 · js · TaskChain · RunSynchronously · method · since 9.5.0.52`

```javascript
var success = RunSynchronously();
```

· return: `boolean`; `true` for success, `false` for failure

Runs the task chain synchronously. Then this method returns after all the tasks in the chain have been run.

Returns true for success, false for failure.

### TaskChain.SleepMs

`Chilkat 11.7.0 · js · TaskChain · SleepMs · method · since 9.5.0.52`

```javascript
SleepMs(numMs);
```

· return: `undefined`  
· numMs: `int`

Convenience method to force the calling thread to sleep for a number of milliseconds.

### TaskChain.Wait

`Chilkat 11.7.0 · js · TaskChain · Wait · method · since 9.5.0.52`

```javascript
var success = Wait(maxWaitMs);
```

· return: `boolean`; `true` for success, `false` for failure  
· maxWaitMs: `int`

Waits for the task chain to complete. Returns when all of the tasks in the chain have completed, or after `maxWaitMs` milliseconds have elapsed. (A `maxWaitMs` value of 0 is to wait indefinitely.) Returns (`false`) if the task chain has not yet been started by calling the Run method, or if the `maxWaitMs` expired. If the task chain completed, was already completed, was canceled, or aborted, then this method returns `true`.

Returns true for success, false for failure.

## Events and callbacks

This binding has no event callbacks.

## Related classes

[`Task`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/js/classes/Task.md)