feat(form): add lazy value definition feature to data

lib/composables/Data.ts

@@ -0,0 +1,108 @@
+import { watchOnce } from '@vueuse/core'
+import cloneDeep from 'lodash-es/cloneDeep'
+import { WatchSource, reactive } from 'vue'
+import { isObject } from '../support/Utils'
+
+export interface Data<T extends Record<string, any>> {
+  state: T
+  init(): void
+}
+
+export type DataWithDef = Record<string, any>
+
+export interface Def<T = any> {
+  __isDef: true
+  value: any
+  source: WatchSource<T>
+  cb: (value: Exclude<T, undefined>) => void
+}
+
+export type UseDataInput<
+  T extends Record<string, any>
+> = T | ((utils: UseDataInputUtils) => DataWithDef)
+
+export interface UseDataInputUtils {
+  def<T>(
+    value: any,
+    source: WatchSource<T>,
+    cb: (value: Exclude<T, undefined>) => void
+  ): Def<T>
+}
+
+export function useData<T extends Record<string, any>>(
+  data: UseDataInput<T>
+): Data<T> {
+  const { state, defs } = createState(data)
+
+  const initialState = cloneDeep(state)
+  const reactiveState = reactive(state)
+
+  handleDefs(defs, reactiveState)
+
+  function init(): void {
+    Object.assign(reactiveState, initialState)
+  }
+
+  return {
+    state: reactiveState,
+    init
+  }
+}
+
+function createState<T extends Record<string, any>>(
+  data: UseDataInput<T>
+): { state: T; defs: [string, Def][] } {
+  if (typeof data !== 'function') {
+    return { state: data, defs: [] }
+  }
+
+  const dataWithDef = data({ def })
+
+  const state = {} as T
+  const defs = [] as [string, Def][]
+
+  for (const key in dataWithDef) {
+    const maybeDef = dataWithDef[key]
+
+    if (!isDef(maybeDef)) {
+      (state as any)[key] = maybeDef
+      continue
+    }
+
+    (state as any)[key] = maybeDef.value
+
+    defs.push([key, maybeDef])
+  }
+
+  return {
+    state,
+    defs
+  }
+}
+
+function handleDefs<T extends Record<string, any>>(
+  defs: [string, Def][], state: T
+): void {
+  defs.forEach(([key, def]) => {
+    watchOnce(def.source, (value: any) => {
+      (state as any)[key] = def.cb(value)
+    })
+  })
+}
+
+function def<T>(
+  value: any,
+  source: WatchSource<T>,
+  cb: (value: Exclude<T, undefined>) => void
+): Def {
+  return {
+    __isDef: true,
+    value,
+    source,
+    cb
+  }
+}
+
+function isDef(value: any): boolean {
+  return isObject(value) ? !!value.__isDef : false
+}

lib/composables/Form.ts

@@ -1,6 +1,6 @@
-import cloneDeep from 'lodash-es/cloneDeep'
-import { Ref, computed, reactive } from 'vue'
+import { Ref, computed } from 'vue'
 import { useSnackbars } from '../stores/Snackbars'
+import { UseDataInput, useData } from './Data'
 import { Validation, useValidation } from './Validation'
 
 export interface Form<T extends Record<string, any>> {
@@ -13,7 +13,7 @@ export interface Form<T extends Record<string, any>> {
 }
 
 export interface UseFormOptions<T extends Record<string, any>> {
-  data: T
+  data: UseDataInput<T>
   rules?: Record<string, any> | ((state: T) => Record<string, any>)
 }
 
@@ -22,20 +22,18 @@ export function useForm<
 >(options: UseFormOptions<T>): Form<T> {
   const snackbars = useSnackbars()
 
-  const initialData = cloneDeep(options.data)
-
-  const data = reactive(options.data)
+  const data = useData(options.data)
 
   const rules = computed(() => {
     return options.rules
-      ? typeof options.rules === 'function' ? options.rules(data) : options.rules
+      ? typeof options.rules === 'function' ? options.rules(data.state) : options.rules
       : {}
   })
 
-  const validation = useValidation(data, rules)
+  const validation = useValidation(data.state, rules)
 
   function init(): void {
-    Object.assign(data, initialData)
+    data.init()
     reset()
   }
 
@@ -61,7 +59,7 @@ export function useForm<
   }
 
   return {
-    data,
+    data: data.state,
     init,
     reset,
     validation,

lib/support/Utils.ts

@@ -13,3 +13,7 @@ export function isNumber(value: unknown): value is number {
 export function isArray(value: unknown): value is unknown[] {
   return Array.isArray(value)
 }
+
+export function isObject(value: unknown): value is Record<string, any> {
+  return typeof value === 'object' && value !== null && !isArray(value)
+}

tests/support/Utils.spec.ts

@@ -41,4 +41,16 @@ describe('support/Utils', () => {
       expect(Utils.isArray([])).toEqual(true)
     })
   })
+
+  describe('isObject', () => {
+    test('check if the given value is object', () => {
+      expect(Utils.isObject(undefined)).toEqual(false)
+      expect(Utils.isObject(null)).toEqual(false)
+      expect(Utils.isObject(1)).toEqual(false)
+      expect(Utils.isObject('a')).toEqual(false)
+      expect(Utils.isObject(true)).toEqual(false)
+      expect(Utils.isObject([])).toEqual(false)
+      expect(Utils.isObject({})).toEqual(true)
+    })
+  })
 })