src/Composer/Installer/InstallationManager.php
public function getInstaller($type)
    {
        $type = strtolower($type);

        if (isset($this->cache[$type])) {
            return $this->cache[$type];
        }

        foreach ($this->installers as $installer) {
            if ($installer->supports($type)) {
                return $this->cache[$type] = $installer;
            }
        }

        throw new \InvalidArgumentException('Unknown installer type: '.$type);
    }
public function getInstaller($type)
    {
        $type = strtolower($type);

        if (isset($this->cache[$type])) {
            return $this->cache[$type];
        }

        foreach ($this->installers as $installer) {
            if ($installer->supports($type)) {
                return $this->cache[$type] = $installer;
            }
        }

        throw new \InvalidArgumentException('Unknown installer type: '.$type);
    }
Returns installer for a specific package type.

@param string $type package type

@throws \InvalidArgumentException if installer for provided type is not registered
@return InstallerInterface