Commanding

This module allow creation of better View Model by adding commanding concept.

Definition

Synchronous command

define(["komvvm/commands"], function(commands) {
    var myCommand = new commands.Command({
        canExecute: function() { return myCondition; },
        execute: function() { /* ... */ }
    });
});

Asynchronous command

define(["komvvm/commands"], function(commands) {
    var myAsyncCommand = new commands.AsyncCommand({
        canExecute: function(isExecuting) { return !isExecuting && myCondition; },
        execute: function(complete) { $.ajax(...).always(complete); }
    });
});

Usage

Binding Handler

<button data-bind="command: myCommand"></button>
<button data-bind="command: myAsyncCommand"></button>

You can customize event :

<button data-bind="command: { click: myCommand, dblclick: myAsyncCommand }"></button>

From javascript

myCommand.execute();
myAsyncCommand.execute();

you can pass argument to execute method :

myCommand.execute(myArg);
myAsyncCommand.execute(myArg);

Objects definitions

Command

Constructor Options

execute

• type: function([$data])
• required

Function to execute when command execution is allowed. Binding handler pass $data to arguments.

canExecute

• type: function
• return type: boolean
• optional
• default: function() { return true; }

Allow to customize when Command can be executed.

context

• type: any
• optional

Custom context to call callbacks with.

Object Properties

canExecute

type: KnockoutComputed
Get if command can be executed.

Object Methods

execute([$data])

$data: any | optional | argument to pass to execute callback.
returns: void
Execute command if possible.

AsyncCommand

Constructor Options

execute

• type: function(complete) | function($data, complete)
• required

Function to execute when command execution is allowed. Call complete argument when execution is complete.
Binding handler pass $data to arguments if callback contains two arguments.

canExecute

• type: function(isExecuting)
• isExecuting: boolean | allow one time execution.
• returns type: boolean
• optional
• default: function() { return true; }

Allow to customize when AsyncCommand can be executed.

context

• type: any
• optional

Custom context to call callbacks with.

Object Properties

canExecute

type: KnockoutComputed
Get if command can be executed.

isExecuting

type: KnockoutObservable
Get if command is executing.

Object Methods

execute([$data])

$data: any | optional | argument to pass to execute callback.
returns: void
Execute command if possible.