multiconf/index.js

Work with JSON configs

// Import.
const fs = require('fs');
const path = require('path');
const JSONCParser = require('./lib/jsonc-parser');

// Constants.
const DEFAULT_CONF_FILES_DIRECTORY = './conf';
const CONF_ENCODING = 'utf8';
const JSONC_CONF_FILES_EXTENSION = '.jsonc';
const CONF_FILES_EXTENSION = '.json';
const DEFAULT_CONF_FILES_EXTENSION = '.json.default';

/**
 * Config.
 */
class Config {
  /**
   * Get.
   * @param {string} [configDir] Config directory.
   * @param {string} [envConfigPrefix] Environment config prefix.
   * @returns {object} Config object.
   */
  static get(configDir = DEFAULT_CONF_FILES_DIRECTORY, envConfigPrefix) {
    // Define config object container.
    const configObject = {};

    // Append file configs if need it.
    FileConfigs.append(configObject, configDir);

    // Append environment configs if need it.
    EnvConfigs.append(configObject, envConfigPrefix);

    // Return config object.
    return configObject;
  }

  static getDefault(configDir = DEFAULT_CONF_FILES_DIRECTORY) {
    // Define config object container.
    const configObject = {};

    // Append file configs if need it.
    FileConfigs.append(configObject, configDir, true);

    // Return config object.
    return configObject;
  }
}

/**
 * File configs.
 */
class FileConfigs {
  /**
   * Append configs from files.
   * @param {object} configObject Config object to handle.
   * @param {string} confDir Config directory.
   * @returns {object} Config object.
   */
  static append(configObject, confDir, defaultOnly = false) {
    // Get files from config directory.
    const files = fs.readdirSync(confDir, CONF_ENCODING);

    // Handle config files.
    for (let i = 0; i < files.length; i++) {
      // File name.
      const file = files[i];

      // If user-defined JSONC config.
      if (file.endsWith(JSONC_CONF_FILES_EXTENSION) && !defaultOnly) {
        const jsonConf = fs.readFileSync(path.join(confDir, file), CONF_ENCODING);
        const confName = file.substring(0, file.length - JSONC_CONF_FILES_EXTENSION.length);
        try {
          configObject[confName] = JSONCParser.parse(jsonConf);
        } catch (error) {
          throw new Error(`Can't parse user-defined config "${confName}".\n${error}`);
        }
      }

      // If user-defined JSON config.
      if (file.endsWith(CONF_FILES_EXTENSION) && !defaultOnly) {
        const jsonConf = fs.readFileSync(path.join(confDir, file), CONF_ENCODING);
        const confName = file.substring(0, file.length - CONF_FILES_EXTENSION.length);
        if (configObject[confName] === undefined) {
          try {
            configObject[confName] = JSON.parse(jsonConf);
          } catch (error) {
            throw new Error(`Can't parse user-defined config "${confName}".\n${error}`);
          }
        }
      }

      // If default config.
      if (file.endsWith(DEFAULT_CONF_FILES_EXTENSION)) {
        const jsonConf = fs.readFileSync(path.join(confDir, file), CONF_ENCODING);
        const confName = file.substring(0, file.length - DEFAULT_CONF_FILES_EXTENSION.length);
        if (configObject[confName] === undefined) {
          try {
            configObject[confName] = JSON.parse(jsonConf);
          } catch (error) {
            throw new Error(`Can't parse default config "${confName}".\n${error}`);
          }
        }
      }
    }

    // Return object with appends.
    return configObject;
  }
}

/**
 * Environment configs.
 */
class EnvConfigs {
  /**
   * Append configs from environment by prefix.
   * @param {object} configObject Config object to handle.
   * @param {string} [envConfigPrefix] Environment config prefix.
   * @returns {object} Config object.
   */
  static append(configObject, envConfigPrefix) {
    // Check.
    if (typeof configObject !== 'object' || typeof envConfigPrefix !== 'string') { return; }

    // Get environment params.
    for (const envParamKey in process.env) {
      // Do not handle if without needed prefix.
      if (!envParamKey.startsWith(envConfigPrefix)) { continue; }

      // Define config key.
      const configKey = envParamKey.substring(envConfigPrefix.length);
      const lowerCaseConfigKey = configKey.toLowerCase();

      // Define config value.
      const configValue = process.env[envParamKey];

      // Try to parse and append config value. Keep original string if can not parse.
      try {
        const configValueObject = JSON.parse(configValue);
        configObject[configKey] = configValueObject;
        configObject[lowerCaseConfigKey] = configValueObject;
      } catch (error) {
        throw new Error(`Can't parse env config "${envParamKey}".\n${error}`);
      }
    }

    // Return object with appends.
    return configObject;
  }
}

// Export.
module.exports = Config;