yii\web\AssetManager::resolveAsset PHP Метод

    protected function resolveAsset($bundle, $asset)
    {
        if (isset($this->assetMap[$asset])) {
            return $this->assetMap[$asset];
        }
        if ($bundle->sourcePath !== null && Url::isRelative($asset)) {
            $asset = $bundle->sourcePath . '/' . $asset;
        }
        $n = mb_strlen($asset, Yii::$app->charset);
        foreach ($this->assetMap as $from => $to) {
            $n2 = mb_strlen($from, Yii::$app->charset);
            if ($n2 <= $n && substr_compare($asset, $from, $n - $n2, $n2) === 0) {
                return $to;
            }
        }
        return false;
    }