#51 onChange prop

README.md

@@ -22,9 +22,10 @@ Features include:
 - [Usage](#usage)
 - [Props overview](#props-overview)
 - [Update functions](#update-functions)
+  - [OnChange function](#onchange-function)
   - [Copy function](#copy-function)
 - [Filter functions](#filter-functions)
-  - [Examples](#examples)
+  - [Examples](#examples-1)
 - [Search/Filtering](#searchfiltering)
 - [Themes \& Styles](#themes--styles)
   - [Fragments](#fragments)
@@ -94,6 +95,7 @@ The only *required* value is `data`.
 | `onEdit`                | `UpdateFunction`                              |             | A function to run whenever a value is **edited**.                                                                                                                                                                                                                                                                    |
 | `onDelete`              | `UpdateFunction`                              |             | A function to run whenever a value is **deleted**.                                                                                                                                                                                                                                                                   |
 | `onAdd`                 | `UpdateFunction`                              |             | A function to run whenever a new property is **added**.                                                                                                                                                                                                                                                              |
+| `onChange`              | `OnChangeFunction`                            |             | A function to modify/constrain user input as they type -- see [OnChange functions](#onchange-function).                                                                                                                                                                                                              |
 | `enableClipboard`       | `boolean\|CopyFunction`                       | `true`      | Whether or not to enable the "Copy to clipboard" button in the UI. If a function is provided, `true` is assumed and this function will be run whenever an item is copied.                                                                                                                                            |
 | `indent`                | `number`                                      | `3`         | Specify the amount of indentation for each level of nesting in the displayed data.                                                                                                                                                                                                                                   |
 | `collapse`              | `boolean\|number\|FilterFunction`             | `false`     | Defines which nodes of the JSON tree will be displayed "opened" in the UI on load. If `boolean`, it'll be either all or none. A `number` specifies a nesting depth after which nodes will be closed. For more fine control a function can be provided — see [Filter functions](#filter-functions).                   |
@@ -140,6 +142,32 @@ The function will receive the following object as a parameter:
 
 The function needn't return anything, but if it returns `false`, it will be considered an error, in which case an error message will displayed in the UI and the internal data state won't actually be updated. If the return value is a `string`, this will be the error message displayed (i.e. you can define your own error messages for updates). On error, the displayed data will revert to its previous value.
 
+### OnChange function
+
+Similar to the Update functions, the `onChange` function is executed as the user input changes. You can use this to restrict or constrain user input -- e.g. limiting numbers to positive values, or preventing line breaks in strings. The function *must* return a value in order to update the user input field, so if no changes are to made, just return it unmodified.
+
+The input object is similar to the Update function input, but with no `newData` field (since this operation occurs before the data is updated).
+
+#### Examples
+
+- Restrict "age" inputs to positive values up to 100:  
+  ```js
+  // in <JsonEditor /> props
+  onChange = ({ newValue, name }) => {
+        if (name === "age" && newValue < 0) return 0;
+        if (name === "age" && newValue > 100) return 100;
+        return newValue
+      }
+  ```
+- Only allow alphabetical or whitespace input for "name" field (including no line breaks):  
+  ```js
+  onChange = ({ newValue, name }) => {
+      if (name === 'name' && typeof newValue === "string")
+        return newValue.replace(/[^a-zA-Z\s]|\n|\r/gm, '');
+      return newValue;
+    }
+  ```
+
 ### Copy function
 
 A similar callback is executed whenever an item is copied to the clipboard (if passed to the `enableClipboard` prop), but with a different input parameter:
@@ -531,7 +559,7 @@ A few helper functions, components and types that might be useful in your own im
 - `Theme`: a full [Theme](#themes--styles) object
 - `ThemeInput`: input type for the `theme` prop
 - `JsonEditorProps`: all input props for the Json Editor component
-- [`UpdateFunction`](#update-functions), [`FilterFunction`](#filter-functions), [`CopyFunction`](#copy-function), [`SearchFilterFunction`](#searchfiltering), [`CompareFunction`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort), [`LocalisedString`](#localisation), [`CustomNodeDefinition`](#custom-nodes), [`CustomTextDefinitions`](#custom-text)
+- [`UpdateFunction`](#update-functions), [`OnChangeFunction`](#onchange-function), [`FilterFunction`](#filter-functions), [`CopyFunction`](#copy-function), [`SearchFilterFunction`](#searchfiltering), [`CompareFunction`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort), [`LocalisedString`](#localisation), [`CustomNodeDefinition`](#custom-nodes), [`CustomTextDefinitions`](#custom-text)
 - `TranslateFunction`: function that takes a [localisation](#localisation) key and returns a translated string
 - `IconReplacements`: input type for the `icons` prop
 - `CollectionNodeProps`: all props passed internally to "collection" nodes (i.e. objects/arrays)

demo/src/App.tsx

@@ -292,6 +292,7 @@ function App() {
               stringTruncate={90}
               customNodeDefinitions={demoData[selectedData]?.customNodeDefinitions}
               customText={demoData[selectedData]?.customTextDefinitions}
+              onChange={demoData[selectedData]?.onChange ?? undefined}
             />
           </Box>
           <VStack w="100%" align="flex-end" gap={4}>

demo/src/demoData/dataDefinitions.tsx

@@ -14,6 +14,7 @@ import {
   CollectionKey,
   DataType,
   DefaultValueFunction,
+  OnChangeFunction,
   SearchFilterFunction,
   ThemeStyles,
   UpdateFunction,
@@ -49,6 +50,7 @@ interface DemoData {
     name: CollectionKey
     path: CollectionKey[]
   }) => any
+  onChange?: OnChangeFunction
   defaultValue?: unknown | DefaultValueFunction
   customNodeDefinitions?: CustomNodeDefinition[]
   customTextDefinitions?: CustomTextDefinitions
@@ -140,9 +142,11 @@ export const demoData: Record<string, DemoData> = {
         <Text>
           You'll note that the <span className="code">id</span> field is not editable, which would
           be important if this saved back to a database. An additional{' '}
-          <span className="code">restrictEdit</span> function as been included which targets the{' '}
-          <span className="code">id</span> field specifically. You also can't add additional fields
-          to the main "Person" objects.
+          <Link href="https://github.com/CarlosNZ/json-edit-react#filter-functions" isExternal>
+            <span className="code">restrictEdit</span> function
+          </Link>{' '}
+          has been included which targets the <span className="code">id</span> field specifically.
+          You also can't add additional fields to the main "Person" objects.
         </Text>
         <Text>
           Also, notice that when you add a new item in the top level array, a correctly structured{' '}
@@ -159,6 +163,14 @@ export const demoData: Record<string, DemoData> = {
           </Link>
           .
         </Text>
+        <Text>
+          Finally, an{' '}
+          <Link href="https://github.com/CarlosNZ/json-edit-react#onchange-function" isExternal>
+            <span className="code">onChange</span> function
+          </Link>{' '}
+          has been added to restrict user input in the <span className="code">name</span> field to
+          alphabetical characters only (with no line breaks too).
+        </Text>
       </Flex>
     ),
     restrictEdit: ({ key, level }) => key === 'id' || level === 0 || level === 1,
@@ -202,6 +214,12 @@ export const demoData: Record<string, DemoData> = {
         }
       return 'New Value'
     },
+    onChange: ({ newValue, name }) => {
+      if (name === 'name') return (newValue as string).replace(/[^a-zA-Z\s]|\n|\r/gm, '')
+      if (['username', 'email', 'phone', 'website'].includes(name as string))
+        return (newValue as string).replace(/\n|\r/gm, '')
+      return newValue
+    },
     data: data.jsonPlaceholder,
   },
   vsCode: {

src/CollectionNode.tsx

@@ -148,6 +148,7 @@ export const CollectionNode: React.FC<CollectionNodeProps> = ({
       const value = JSON5.parse(stringifiedValue)
       setIsEditing(false)
       setError(null)
+      if (JSON.stringify(value) === JSON.stringify(data)) return
       onEdit(value, path).then((error) => {
         if (error) showError(error)
       })
@@ -160,6 +161,7 @@ export const CollectionNode: React.FC<CollectionNodeProps> = ({
 
   const handleEditKey = (newKey: string) => {
     setIsEditingKey(false)
+    if (name === newKey) return
     if (!parentData) return
     const parentPath = path.slice(0, -1)
     if (!newKey) return

src/JsonEditor.tsx

@@ -7,7 +7,7 @@ import {
   type CollectionData,
   type JsonEditorProps,
   type FilterFunction,
-  type OnChangeFunction,
+  type InternalUpdateFunction,
   type NodeData,
   type SearchFilterFunction,
 } from './types'
@@ -26,6 +26,7 @@ const Editor: React.FC<JsonEditorProps> = ({
   onEdit: srcEdit = onUpdate,
   onDelete: srcDelete = onUpdate,
   onAdd: srcAdd = onUpdate,
+  onChange,
   enableClipboard = true,
   theme = 'default',
   icons,
@@ -89,13 +90,15 @@ const Editor: React.FC<JsonEditorProps> = ({
     fullData: data,
   }
 
-  const onEdit: OnChangeFunction = async (value, path) => {
+  const onEdit: InternalUpdateFunction = async (value, path) => {
     const { currentData, newData, currentValue, newValue } = updateDataObject(
       data,
       path,
       value,
       'update'
     )
+    if (currentValue === newValue) return
+
     setData(newData)
 
     const result = await srcEdit({
@@ -112,7 +115,7 @@ const Editor: React.FC<JsonEditorProps> = ({
     }
   }
 
-  const onDelete: OnChangeFunction = async (value, path) => {
+  const onDelete: InternalUpdateFunction = async (value, path) => {
     const { currentData, newData, currentValue, newValue } = updateDataObject(
       data,
       path,
@@ -135,7 +138,7 @@ const Editor: React.FC<JsonEditorProps> = ({
     }
   }
 
-  const onAdd: OnChangeFunction = async (value, path) => {
+  const onAdd: InternalUpdateFunction = async (value, path) => {
     const { currentData, newData, currentValue, newValue } = updateDataObject(
       data,
       path,
@@ -169,6 +172,7 @@ const Editor: React.FC<JsonEditorProps> = ({
     onEdit,
     onDelete,
     onAdd,
+    onChange,
     showCollectionCount,
     collapseFilter,
     restrictEditFilter,

src/ValueNodeWrapper.tsx

@@ -1,4 +1,4 @@
-import React, { useEffect, useState, useMemo } from 'react'
+import React, { useEffect, useState, useMemo, useCallback } from 'react'
 import {
   StringValue,
   NumberValue,
@@ -32,6 +32,7 @@ export const ValueNodeWrapper: React.FC<ValueNodeProps> = (props) => {
     nodeData,
     onEdit,
     onDelete,
+    onChange,
     enableClipboard,
     restrictEditFilter,
     restrictDeleteFilter,
@@ -59,6 +60,25 @@ export const ValueNodeWrapper: React.FC<ValueNodeProps> = (props) => {
   const customNodeData = getCustomNode(customNodeDefinitions, nodeData)
   const [dataType, setDataType] = useState<DataType | string>(getDataType(data, customNodeData))
 
+  const updateValue = useCallback(
+    (newValue: ValueData) => {
+      if (!onChange) {
+        setValue(newValue)
+        return
+      }
+
+      const modifiedValue = onChange({
+        currentData: nodeData.fullData,
+        newValue,
+        currentValue: value as ValueData,
+        name,
+        path,
+      })
+      setValue(modifiedValue)
+    },
+    [onChange]
+  )
+
   useEffect(() => {
     setValue(typeof data === 'function' ? INVALID_FUNCTION_STRING : data)
     setDataType(getDataType(data, customNodeData))
@@ -113,7 +133,7 @@ export const ValueNodeWrapper: React.FC<ValueNodeProps> = (props) => {
         // that won't match the custom node condition any more
         customNodeData?.CustomNode ? translate('DEFAULT_STRING', nodeData) : undefined
       )
-      setValue(newValue as ValueData | CollectionData)
+      updateValue(newValue as ValueData)
       onEdit(newValue, path)
       setDataType(type)
     }
@@ -151,6 +171,7 @@ export const ValueNodeWrapper: React.FC<ValueNodeProps> = (props) => {
 
   const handleEditKey = (newKey: string) => {
     setIsEditingKey(false)
+    if (name === newKey) return
     if (!parentData) return
     const parentPath = path.slice(0, -1)
     if (!newKey) return
@@ -186,7 +207,7 @@ export const ValueNodeWrapper: React.FC<ValueNodeProps> = (props) => {
   const inputProps = {
     value,
     parentData,
-    setValue,
+    setValue: updateValue,
     isEditing,
     setIsEditing: canEdit ? () => setIsEditing(true) : () => {},
     handleEdit,
@@ -204,7 +225,7 @@ export const ValueNodeWrapper: React.FC<ValueNodeProps> = (props) => {
         {...props}
         value={value}
         customNodeProps={customNodeProps}
-        setValue={setValue}
+        setValue={updateValue}
         handleEdit={handleEdit}
         handleCancel={handleCancel}
         handleKeyPress={(e: React.KeyboardEvent) => {

src/ValueNodes.tsx

@@ -77,11 +77,11 @@ export const NumberValue: React.FC<InputProps & { value: number }> = ({
         break
       case 'ArrowUp':
         e.preventDefault()
-        setValue((prev) => Number(prev) + 1)
+        setValue(Number(value) + 1)
         break
       case 'ArrowDown':
         e.preventDefault()
-        setValue((prev) => Number(prev) - 1)
+        setValue(Number(value) - 1)
     }
   }
 

src/index.ts

@@ -2,6 +2,7 @@ import JsonEditor from './JsonEditor'
 import {
   type JsonEditorProps,
   type UpdateFunction,
+  type OnChangeFunction,
   type CopyFunction,
   type FilterFunction,
   type SearchFilterFunction,
@@ -34,6 +35,7 @@ export {
   type ThemeInput,
   type JsonEditorProps,
   type UpdateFunction,
+  type OnChangeFunction,
   type CopyFunction,
   type FilterFunction,
   type SearchFilterFunction,