getCachedConfigArrayForFile(filePath) {
		assertValidFilePath(filePath);

		debug(`Looking up cached config for ${filePath}`);

		return this.getCachedConfigArrayForPath(path.dirname(filePath));
	}
Returns a configuration array for the given file based on the CLI options.
This is a synchronous operation and does not read any files from disk. It's
intended to be used in locations where we know the config file has already
been loaded and we just need to get the configuration for a file.
@param {string} filePath The path of the file to retrieve a config object for.
@returns {FlatConfigArray} A configuration object for the file.
@throws {Error} If `filePath` is not a non-empty string.
@throws {Error} If `filePath` is not an absolute path.
@throws {Error} If the config file was not already loaded.