'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