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CommandInterceptor.js
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CommandInterceptor.js
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import {
forEach,
isFunction,
isArray,
isNumber,
isObject
} from 'min-dash';
var DEFAULT_PRIORITY = 1000;
/**
* A utility that can be used to plug-in into the command execution for
* extension and/or validation.
*
* @param {EventBus} eventBus
*
* @example
*
* import inherits from 'inherits';
*
* import CommandInterceptor from 'diagram-js/lib/command/CommandInterceptor';
*
* function CommandLogger(eventBus) {
* CommandInterceptor.call(this, eventBus);
*
* this.preExecute(function(event) {
* console.log('command pre-execute', event);
* });
* }
*
* inherits(CommandLogger, CommandInterceptor);
*
*/
export default function CommandInterceptor(eventBus) {
this._eventBus = eventBus;
}
CommandInterceptor.$inject = [ 'eventBus' ];
function unwrapEvent(fn, that) {
return function(event) {
return fn.call(that || null, event.context, event.command, event);
};
}
/**
* Register an interceptor for a command execution
*
* @param {String|Array<String>} [events] list of commands to register on
* @param {String} [hook] command hook, i.e. preExecute, executed to listen on
* @param {Number} [priority] the priority on which to hook into the execution
* @param {Function} handlerFn interceptor to be invoked with (event)
* @param {Boolean} unwrap if true, unwrap the event and pass (context, command, event) to the
* listener instead
* @param {Object} [that] Pass context (`this`) to the handler function
*/
CommandInterceptor.prototype.on = function(events, hook, priority, handlerFn, unwrap, that) {
if (isFunction(hook) || isNumber(hook)) {
that = unwrap;
unwrap = handlerFn;
handlerFn = priority;
priority = hook;
hook = null;
}
if (isFunction(priority)) {
that = unwrap;
unwrap = handlerFn;
handlerFn = priority;
priority = DEFAULT_PRIORITY;
}
if (isObject(unwrap)) {
that = unwrap;
unwrap = false;
}
if (!isFunction(handlerFn)) {
throw new Error('handlerFn must be a function');
}
if (!isArray(events)) {
events = [ events ];
}
var eventBus = this._eventBus;
forEach(events, function(event) {
// concat commandStack(.event)?(.hook)?
var fullEvent = [ 'commandStack', event, hook ].filter(function(e) { return e; }).join('.');
eventBus.on(fullEvent, priority, unwrap ? unwrapEvent(handlerFn, that) : handlerFn, that);
});
};
var hooks = [
'canExecute',
'preExecute',
'preExecuted',
'execute',
'executed',
'postExecute',
'postExecuted',
'revert',
'reverted'
];
/*
* Install hook shortcuts
*
* This will generate the CommandInterceptor#(preExecute|...|reverted) methods
* which will in term forward to CommandInterceptor#on.
*/
forEach(hooks, function(hook) {
/**
* {canExecute|preExecute|preExecuted|execute|executed|postExecute|postExecuted|revert|reverted}
*
* A named hook for plugging into the command execution
*
* @param {String|Array<String>} [events] list of commands to register on
* @param {Number} [priority] the priority on which to hook into the execution
* @param {Function} handlerFn interceptor to be invoked with (event)
* @param {Boolean} [unwrap=false] if true, unwrap the event and pass (context, command, event) to the
* listener instead
* @param {Object} [that] Pass context (`this`) to the handler function
*/
CommandInterceptor.prototype[hook] = function(events, priority, handlerFn, unwrap, that) {
if (isFunction(events) || isNumber(events)) {
that = unwrap;
unwrap = handlerFn;
handlerFn = priority;
priority = events;
events = null;
}
this.on(events, hook, priority, handlerFn, unwrap, that);
};
});