| |
| 'use strict' |
| const fs = require('fs') |
| const path = require('path') |
| const YError = require('./yerror') |
| |
| let previouslyVisitedConfigs = [] |
| |
| function checkForCircularExtends (cfgPath) { |
| if (previouslyVisitedConfigs.indexOf(cfgPath) > -1) { |
| throw new YError(`Circular extended configurations: '${cfgPath}'.`) |
| } |
| } |
| |
| function getPathToDefaultConfig (cwd, pathToExtend) { |
| return path.resolve(cwd, pathToExtend) |
| } |
| |
| function applyExtends (config, cwd) { |
| let defaultConfig = {} |
| |
| if (config.hasOwnProperty('extends')) { |
| if (typeof config.extends !== 'string') return defaultConfig |
| const isPath = /\.json|\..*rc$/.test(config.extends) |
| let pathToDefault = null |
| if (!isPath) { |
| try { |
| pathToDefault = require.resolve(config.extends) |
| } catch (err) { |
| // most likely this simply isn't a module. |
| } |
| } else { |
| pathToDefault = getPathToDefaultConfig(cwd, config.extends) |
| } |
| // maybe the module uses key for some other reason, |
| // err on side of caution. |
| if (!pathToDefault && !isPath) return config |
| |
| checkForCircularExtends(pathToDefault) |
| |
| previouslyVisitedConfigs.push(pathToDefault) |
| |
| defaultConfig = isPath ? JSON.parse(fs.readFileSync(pathToDefault, 'utf8')) : require(config.extends) |
| delete config.extends |
| defaultConfig = applyExtends(defaultConfig, path.dirname(pathToDefault)) |
| } |
| |
| previouslyVisitedConfigs = [] |
| |
| return Object.assign({}, defaultConfig, config) |
| } |
| |
| module.exports = applyExtends |
