src/Composer/EventDispatcher/EventDispatcher.php
protected function getScriptListeners(Event $event)
    {
        $package = $this->composer->getPackage();
        $scripts = $package->getScripts();

        if (empty($scripts[$event->getName()])) {
            return array();
        }

        if ($this->loader) {
            $this->loader->unregister();
        }

        $generator = $this->composer->getAutoloadGenerator();
        if ($event instanceof ScriptEvent) {
            $generator->setDevMode($event->isDevMode());
        }

        $packages = $this->composer->getRepositoryManager()->getLocalRepository()->getCanonicalPackages();
        $packageMap = $generator->buildPackageMap($this->composer->getInstallationManager(), $package, $packages);
        $map = $generator->parseAutoloads($packageMap, $package);
        $this->loader = $generator->createLoader($map);
        $this->loader->register();

        return $scripts[$event->getName()];
    }
protected function getScriptListeners(Event $event)
    {
        $package = $this->composer->getPackage();
        $scripts = $package->getScripts();

        if (empty($scripts[$event->getName()])) {
            return array();
        }

        if ($this->loader) {
            $this->loader->unregister();
        }

        $generator = $this->composer->getAutoloadGenerator();
        if ($event instanceof ScriptEvent) {
            $generator->setDevMode($event->isDevMode());
        }

        $packages = $this->composer->getRepositoryManager()->getLocalRepository()->getCanonicalPackages();
        $packageMap = $generator->buildPackageMap($this->composer->getInstallationManager(), $package, $packages);
        $map = $generator->parseAutoloads($packageMap, $package);
        $this->loader = $generator->createLoader($map);
        $this->loader->register();

        return $scripts[$event->getName()];
    }
Finds all listeners defined as scripts in the package

@param  Event $event Event object
@return array Listeners