#119 dialog for editing rgroup does not work

- add FormContext & useFormContext hook
- update rgroup-logic.jsx

src/contexts/formContext.tsx

@@ -0,0 +1,5 @@
+import React from 'react'
+
+const formContext = React.createContext(null)
+
+export default formContext

src/contexts/index.ts

@@ -1,4 +1,5 @@
 import SettingsContext, { ISettingsContext } from './settingsContext'
+import FormContext from './formContext'
 
-export { SettingsContext }
+export { SettingsContext, FormContext }
 export type { ISettingsContext }

src/hooks/index.ts

@@ -1,3 +1,4 @@
 import useSettingsContext from './useSettingsContext'
+import useFormContext from './useFormContext'
 
-export { useSettingsContext }
+export { useSettingsContext, useFormContext }

src/hooks/useFormContext.tsx

@@ -0,0 +1,6 @@
+import React from 'react'
+import FormContext from './../contexts/formContext'
+
+export default function useFormContext() {
+  return React.useContext(FormContext)
+}

src/script/ui/component/form/form.jsx

@@ -21,9 +21,8 @@ import classNames from 'classnames'
 
 import Input from './input'
 import { updateFormState } from '../../state/modal/form'
-import { useContext } from 'react'
-
-const FormContext = React.createContext(null)
+import { FormContext } from './../../../../contexts'
+import { useFormContext } from './../../../../hooks'
 
 class Form extends Component {
   constructor(props) {
@@ -100,7 +99,7 @@ function Label({ labelPos, title, children, ...props }) {
 
 function Field(props) {
   const { name, onChange, component, labelPos, ...prop } = props
-  const { schema, stateStore } = useContext(FormContext)
+  const { schema, stateStore } = useFormContext()
   const desc = prop.schema || schema.properties[name]
   const { dataError, ...fieldOpts } = stateStore.field(name, onChange)
   const Component = component

src/script/ui/dialog/toolbox/rgroup-logic.jsx

@@ -20,10 +20,11 @@ import { connect } from 'react-redux'
 import { rgroupLogic as rgroupSchema } from '../../data/schema/struct-schema'
 import Form, { Field } from '../../component/form/form'
 import Dialog from '../../component/dialog'
+import { useFormContext } from './../../../../hooks'
 
-function IfThenSelect(props, { schema }) {
+function IfThenSelect(props) {
   const { name, rgids } = props
-
+  const { schema } = useFormContext()
   const desc = {
     title: schema.properties[name].title,
     enum: [0],