src/vs/workbench/services/configuration/browser/configuration.ts/FileServiceBasedConfiguration/resolveContents
class FileServiceBasedConfiguration:	async resolveContents(): Promise<[string | undefined, [string, string | undefined][]]> {

		const resolveContents = async (resources: URI[]): Promise<(string | undefined)[]> => {
			return Promise.all(resources.map(async resource => {
				try {
					const content = (await this.fileService.readFile(resource)).value.toString();
					return content;
				} catch (error) {
					this.logService.trace(`Error while resolving configuration file '${resource.toString()}': ${errors.getErrorMessage(error)}`);
					if ((<FileOperationError>error).fileOperationResult !== FileOperationResult.FILE_NOT_FOUND
						&& (<FileOperationError>error).fileOperationResult !== FileOperationResult.FILE_NOT_DIRECTORY) {
						this.logService.error(error);
					}
				}
				return '{}';
			}));
		};

		const [[settingsContent], standAloneConfigurationContents] = await Promise.all([
			resolveContents([this.settingsResource]),
			resolveContents(this.standAloneConfigurationResources.map(([, resource]) => resource)),
		]);

		return [settingsContent, standAloneConfigurationContents.map((content, index) => ([this.standAloneConfigurationResources[index][0], content]))];
	}