var defaultIsMergeableObject = require('is-mergeable-object') function emptyTarget(val) { return Array.isArray(val) ? [] : {} } function cloneUnlessOtherwiseSpecified(value, options) { return (options.clone !== false && options.isMergeableObject(value)) ? deepmerge(emptyTarget(value), value, options) : value } function defaultArrayMerge(target, source, options) { return target.concat(source).map(function(element) { return cloneUnlessOtherwiseSpecified(element, options) }) } function getMergeFunction(key, options) { if (!options.customMerge) { return deepmerge } var customMerge = options.customMerge(key) return typeof customMerge === 'function' ? customMerge : deepmerge } function getEnumerableOwnPropertySymbols(target) { return Object.getOwnPropertySymbols ? Object.getOwnPropertySymbols(target).filter(function(symbol) { return Object.propertyIsEnumerable.call(target, symbol) }) : [] } function getKeys(target) { return Object.keys(target).concat(getEnumerableOwnPropertySymbols(target)) } function propertyIsOnObject(object, property) { try { return property in object } catch(_) { return false } } // Protects from prototype poisoning and unexpected merging up the prototype chain. function propertyIsUnsafe(target, key) { return propertyIsOnObject(target, key) // Properties are safe to merge if they don't exist in the target yet, && !(Object.hasOwnProperty.call(target, key) // unsafe if they exist up the prototype chain, && Object.propertyIsEnumerable.call(target, key)) // and also unsafe if they're nonenumerable. } function mergeObject(target, source, options) { var destination = {} if (options.isMergeableObject(target)) { getKeys(target).forEach(function(key) { destination[key] = cloneUnlessOtherwiseSpecified(target[key], options) }) } getKeys(source).forEach(function(key) { if (propertyIsUnsafe(target, key)) { return } if (propertyIsOnObject(target, key) && options.isMergeableObject(source[key])) { destination[key] = getMergeFunction(key, options)(target[key], source[key], options) } else { destination[key] = cloneUnlessOtherwiseSpecified(source[key], options) } }) return destination } function deepmerge(target, source, options) { options = options || {} options.arrayMerge = options.arrayMerge || defaultArrayMerge options.isMergeableObject = options.isMergeableObject || defaultIsMergeableObject // cloneUnlessOtherwiseSpecified is added to `options` so that custom arrayMerge() // implementations can use it. The caller may not replace it. options.cloneUnlessOtherwiseSpecified = cloneUnlessOtherwiseSpecified var sourceIsArray = Array.isArray(source) var targetIsArray = Array.isArray(target) var sourceAndTargetTypesMatch = sourceIsArray === targetIsArray if (!sourceAndTargetTypesMatch) { return cloneUnlessOtherwiseSpecified(source, options) } else if (sourceIsArray) { return options.arrayMerge(target, source, options) } else { return mergeObject(target, source, options) } } deepmerge.all = function deepmergeAll(array, options) { if (!Array.isArray(array)) { throw new Error('first argument should be an array') } return array.reduce(function(prev, next) { return deepmerge(prev, next, options) }, {}) } module.exports = deepmerge