@soundstep/soma/src/commands.js

Soma is a javascript framework created to build scalable and maintainable applications.

import utils from './utils';

function interceptorHandler(injector, id, CommandClass, signal, binding) {
    const args = Array.prototype.slice.call(arguments, 5);
    const childInjector = injector.createChild();
    childInjector.mapValue('id', id);
    childInjector.mapValue('signal', signal);
    childInjector.mapValue('binding', binding);
    const command = childInjector.createInstance(CommandClass);
    if (typeof command.execute === 'function') {
        command.execute.apply(command, args);
    }
    childInjector.dispose();
}

function addInterceptor(scope, id, CommandClass) {
    const binding = scope.emitter.addListener(id, interceptorHandler, scope);
    binding.params = [scope.injector, id, CommandClass, scope.emitter.getSignal(id), binding];
    return binding;
}

function removeInterceptor(scope, id) {
    const signal = scope.emitter.getSignal(id);
    if (signal) {
        signal.removeAll();
    }
}

function commandOptions(binding) {
    return {
        setInjector: function(injector) {
            if (binding && injector) {
                binding.params[0] = injector;
            }
            return commandOptions(binding);
        }
    };
}

const Commands = function(emitter, injector) {
    this.list = {};
    this.emitter = emitter;
    this.injector = injector;
};

Commands.prototype.add = function(id, CommandClass) {
    if (this.list[id]) {
        throw new Error('[Commands] Error: a command with the id: "' + id + '" has already been registered');
    }
    this.list[id] = CommandClass;
    const binding = addInterceptor(this, id, CommandClass);
    return commandOptions(binding);
};

Commands.prototype.get = function(id) {
    return this.list[id];
};

Commands.prototype.remove = function(id) {
    if (this.list[id]) {
        this.list[id] = undefined;
        delete this.list[id];
        removeInterceptor(this, id);
    }
};

Commands.prototype.dispose = function() {
    for (const id in this.list) {
        this.remove(id);
    }
    this.list = {};
    this.emitter = undefined;
    this.injector = undefined;
};

Commands.extend = function(obj) {
    return utils.inherit(Commands, obj);
};

export default Commands;