index.js 2.4 KB

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  1. var defaultIsMergeableObject = require('is-mergeable-object')
  2. function emptyTarget(val) {
  3. return Array.isArray(val) ? [] : {}
  4. }
  5. function cloneUnlessOtherwiseSpecified(value, options) {
  6. return (options.clone !== false && options.isMergeableObject(value))
  7. ? deepmerge(emptyTarget(value), value, options)
  8. : value
  9. }
  10. function defaultArrayMerge(target, source, options) {
  11. return target.concat(source).map(function(element) {
  12. return cloneUnlessOtherwiseSpecified(element, options)
  13. })
  14. }
  15. function getMergeFunction(key, options) {
  16. if (!options.customMerge) {
  17. return deepmerge
  18. }
  19. var customMerge = options.customMerge(key)
  20. return typeof customMerge === 'function' ? customMerge : deepmerge
  21. }
  22. function getEnumerableOwnPropertySymbols(target) {
  23. return Object.getOwnPropertySymbols
  24. ? Object.getOwnPropertySymbols(target).filter(function(symbol) {
  25. return target.propertyIsEnumerable(symbol)
  26. })
  27. : []
  28. }
  29. function getKeys(target) {
  30. return Object.keys(target).concat(getEnumerableOwnPropertySymbols(target))
  31. }
  32. function mergeObject(target, source, options) {
  33. var destination = {}
  34. if (options.isMergeableObject(target)) {
  35. getKeys(target).forEach(function(key) {
  36. destination[key] = cloneUnlessOtherwiseSpecified(target[key], options)
  37. })
  38. }
  39. getKeys(source).forEach(function(key) {
  40. if (!options.isMergeableObject(source[key]) || !target[key]) {
  41. destination[key] = cloneUnlessOtherwiseSpecified(source[key], options)
  42. } else {
  43. destination[key] = getMergeFunction(key, options)(target[key], source[key], options)
  44. }
  45. })
  46. return destination
  47. }
  48. function deepmerge(target, source, options) {
  49. options = options || {}
  50. options.arrayMerge = options.arrayMerge || defaultArrayMerge
  51. options.isMergeableObject = options.isMergeableObject || defaultIsMergeableObject
  52. var sourceIsArray = Array.isArray(source)
  53. var targetIsArray = Array.isArray(target)
  54. var sourceAndTargetTypesMatch = sourceIsArray === targetIsArray
  55. if (!sourceAndTargetTypesMatch) {
  56. return cloneUnlessOtherwiseSpecified(source, options)
  57. } else if (sourceIsArray) {
  58. return options.arrayMerge(target, source, options)
  59. } else {
  60. return mergeObject(target, source, options)
  61. }
  62. }
  63. deepmerge.all = function deepmergeAll(array, options) {
  64. if (!Array.isArray(array)) {
  65. throw new Error('first argument should be an array')
  66. }
  67. return array.reduce(function(prev, next) {
  68. return deepmerge(prev, next, options)
  69. }, {})
  70. }
  71. module.exports = deepmerge