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JavaScript

import DeveloperError from "../Core/DeveloperError.js";
/**
* A Command is a function with an extra <code>canExecute</code> observable property to determine
* whether the command can be executed. When executed, a Command function will check the
* value of <code>canExecute</code> and throw if false.
*
* This type describes an interface and is not intended to be instantiated directly.
* See {@link createCommand} to create a command from a function.
*
* @alias Command
* @constructor
*/
function Command() {
/**
* Gets whether this command can currently be executed. This property is observable.
* @type {Boolean}
* @default undefined
*/
this.canExecute = undefined;
/**
* Gets an event which is raised before the command executes, the event
* is raised with an object containing two properties: a <code>cancel</code> property,
* which if set to false by the listener will prevent the command from being executed, and
* an <code>args</code> property, which is the array of arguments being passed to the command.
* @type {Event}
* @default undefined
*/
this.beforeExecute = undefined;
/**
* Gets an event which is raised after the command executes, the event
* is raised with the return value of the command as its only parameter.
* @type {Event}
* @default undefined
*/
this.afterExecute = undefined;
DeveloperError.throwInstantiationError();
}
export default Command;