feat(Form): support preferMarginToDisplayHelp, close #4641

src/form/error.jsx

@@ -25,10 +25,12 @@ class Error extends React.Component {
          */
         children: PropTypes.oneOfType([PropTypes.node, PropTypes.func]),
         prefix: PropTypes.string,
+        preferMarginToDisplayHelp: PropTypes.bool,
     };
 
     static defaultProps = {
         prefix: 'next-',
+        preferMarginToDisplayHelp: false,
     };
 
     static contextTypes = {
@@ -42,13 +44,22 @@ class Error extends React.Component {
     };
 
     render() {
-        const { children, name, prefix, style, className, field: _field, ...others } = this.props;
+        const {
+            children,
+            name,
+            prefix,
+            style,
+            className,
+            field: _field,
+            preferMarginToDisplayHelp,
+            ...others
+        } = this.props;
 
         if (children && typeof children !== 'function') {
             return (
                 <div className={`${prefix}form-item-help`}>
                     {children}
-                    <div className={`${prefix}form-item-help-margin-offset`} />
+                    {!!preferMarginToDisplayHelp && <div className={`${prefix}form-item-help-margin-offset`} />}
                 </div>
             );
         }
@@ -92,7 +103,7 @@ class Error extends React.Component {
         return (
             <div {...others} className={cls} style={style}>
                 {result}
-                <div className={`${prefix}form-item-help-margin-offset`} />
+                {!!preferMarginToDisplayHelp && <div className={`${prefix}form-item-help-margin-offset`} />}
             </div>
         );
     }

src/form/form.jsx

@@ -142,6 +142,12 @@ export default class Form extends React.Component {
          * @version 1.20
          */
         useLabelForErrorMessage: PropTypes.bool,
+        /**
+         * 倾向使用item的margin空间来展示help
+         * @default false
+         * @version 1.26.37
+         */
+        preferMarginToDisplayHelp: PropTypes.bool,
         /**
          * 表示是否显示 label 后面的冒号
          * @version 1.22
@@ -166,6 +172,7 @@ export default class Form extends React.Component {
         device: 'desktop',
         colon: false,
         disabled: false,
+        preferMarginToDisplayHelp: false,
     };
 
     static childContextTypes = {
@@ -175,6 +182,7 @@ export default class Form extends React.Component {
         _formPreview: PropTypes.bool,
         _formFullWidth: PropTypes.bool,
         _formLabelForErrorMessage: PropTypes.bool,
+        _formMarginToDisplayHelp: PropTypes.bool,
     };
 
     constructor(props) {
@@ -216,6 +224,7 @@ export default class Form extends React.Component {
             _formPreview: this.props.isPreview,
             _formFullWidth: this.props.fullWidth,
             _formLabelForErrorMessage: this.props.useLabelForErrorMessage,
+            _formMarginToDisplayHelp: this.props.preferMarginToDisplayHelp,
         };
     }
 

src/form/item.jsx

@@ -213,6 +213,12 @@ export default class Item extends React.Component {
          * 是否使用 label 替换校验信息的 name 字段
          */
         useLabelForErrorMessage: PropTypes.bool,
+        /**
+         * 倾向使用item的margin空间来展示help
+         * @default false
+         * @version 1.26.37
+         */
+        preferMarginToDisplayHelp: PropTypes.bool,
         /**
          * 表示是否显示 label 后面的冒号
          */
@@ -240,6 +246,7 @@ export default class Item extends React.Component {
         _formPreview: PropTypes.bool,
         _formFullWidth: PropTypes.bool,
         _formLabelForErrorMessage: PropTypes.bool,
+        _formMarginToDisplayHelp: PropTypes.bool,
     };
 
     static _typeMark = 'form_item';
@@ -268,11 +275,18 @@ export default class Item extends React.Component {
     }
 
     getHelper(children) {
-        const help = this.props.help;
-        const _formField = this.context._formField;
+        const { help, preferMarginToDisplayHelp } = this.props;
+        const { _formField, _formMarginToDisplayHelp } = this.context;
+
+        const useMargin =
+            typeof preferMarginToDisplayHelp !== 'undefined' ? preferMarginToDisplayHelp : _formMarginToDisplayHelp;
 
         return (
-            <Error name={help === undefined ? this.getNames(children) : undefined} field={_formField}>
+            <Error
+                name={help === undefined ? this.getNames(children) : undefined}
+                field={_formField}
+                preferMarginToDisplayHelp={useMargin}
+            >
                 {help}
             </Error>
         );

src/form/main.scss

@@ -41,6 +41,10 @@
 
         #{$form-prefix}-item {
             margin-bottom: 0;
+
+            .#{$css-prefix}form-item-help-margin-offset {
+                margin-top: 0;
+            }
         }
 
         #{$form-prefix}-item.#{$css-prefix}left {
@@ -151,6 +155,10 @@
             #{$form-prefix}-item-label {
                 font-size: $form-element-large-font-size;
             }
+
+            .#{$css-prefix}form-item-help-margin-offset {
+                margin-top: -$form-item-l-margin-b;
+            }
         }
         &.#{$css-prefix}small {
             margin-bottom: $form-item-s-margin-b;
@@ -165,6 +173,10 @@
             #{$form-prefix}-item-label {
                 font-size: $form-element-small-font-size;
             }
+
+            .#{$css-prefix}form-item-help-margin-offset {
+                margin-top: -$form-item-s-margin-b;
+            }
         }
         &.#{$css-prefix}top > #{$form-prefix}-item-label {
             margin-bottom: $form-top-label-margin-b;

test/form/validate-spec.js

@@ -1,5 +1,4 @@
 import React from 'react';
-import ReactDOM from 'react-dom';
 import ReactTestUtils from 'react-dom/test-utils';
 import Enzyme, { mount } from 'enzyme';
 import Adapter from 'enzyme-adapter-react-16';
@@ -8,10 +7,13 @@ import Input from '../../src/input';
 import Form from '../../src/form/index';
 import Field from '../../src/field';
 import { dom } from '../../src/util';
+import testUtil from '../util/index';
+
 const FormItem = Form.Item;
 const Submit = Form.Submit;
 const Reset = Form.Reset;
 const { getStyle } = dom;
+const { render } = testUtil;
 Enzyme.configure({ adapter: new Adapter() });
 
 describe('Submit', () => {
@@ -445,46 +447,69 @@ describe('Reset', () => {
 });
 
 describe('Error', () => {
-    let mountNode;
-
     const getVerDistance = (node1, node2) => {
         const rect1 = node1.getBoundingClientRect();
         const rect2 = node2.getBoundingClientRect();
         return rect2.top - rect1.top - rect1.height;
     };
 
-    beforeEach(() => {
-        mountNode = document.createElement('div');
-        document.body.appendChild(mountNode);
-    });
+    describe('preferMarginToDisplayHelp', () => {
+        const getDistance = wrapper => {
+            const items = wrapper.find('.next-form-item');
+            assert(items.length === 3);
+            return getVerDistance(items[0].querySelector('.next-input'), items[1]);
+        };
+        function Demo({ formUseMargin, itemUseMargin }) {
+            return (
+                <Form preferMarginToDisplayHelp={formUseMargin}>
+                    <FormItem label="item1" required preferMarginToDisplayHelp={itemUseMargin}>
+                        <Input name="name" />
+                    </FormItem>
+                    <FormItem label="item2">
+                        <Input name="name2" />
+                    </FormItem>
+                    <FormItem>
+                        <Form.Submit validate>submit</Form.Submit>
+                    </FormItem>
+                </Form>
+            );
+        }
+        it('form should support preferMarginToDisplayHelp', () => {
+            const wrapper = render(<Demo />);
 
-    afterEach(() => {
-        ReactDOM.unmountComponentAtNode(mountNode);
-        document.body.removeChild(mountNode);
-    });
+            ReactTestUtils.Simulate.click(wrapper.find('.next-btn')[0]);
+            const oldDistance = getDistance(wrapper);
 
-    it('the error does not affect the style', () => {
-        ReactDOM.render(
-            <Form>
-                <FormItem label="item1" required>
-                    <Input />
-                </FormItem>
-                <FormItem label="item2">
-                    <Input />
-                </FormItem>
-                <FormItem>
-                    <Form.Submit>submit</Form.Submit>
-                </FormItem>
-            </Form>,
-            mountNode
-        );
+            wrapper.setProps({ formUseMargin: true });
+            const newDistance = getDistance(wrapper);
+
+            assert(newDistance < oldDistance);
+
+            wrapper.unmount();
+        });
+        it('form item should support preferMarginToDisplayHelp', () => {
+            const wrapper = render(<Demo />);
+            ReactTestUtils.Simulate.click(wrapper.find('.next-btn')[0]);
+            const oldDistance = getDistance(wrapper);
+
+            wrapper.setProps({ itemUseMargin: true });
+            const newDistance = getDistance(wrapper);
+
+            assert(newDistance < oldDistance);
+
+            wrapper.unmount();
+        });
+        it('form item > form when cross preferMarginToDisplayHelp at same time', () => {
+            const wrapper = render(<Demo />);
+            ReactTestUtils.Simulate.click(wrapper.find('.next-btn')[0]);
+            const oldDistance = getDistance(wrapper);
+
+            wrapper.setProps({ formUseMargin: false, itemUseMargin: true });
+            const newDistance = getDistance(wrapper);
 
-        const items = mountNode.querySelectorAll('.next-form-item');
-        assert(items.length === 3);
+            assert(newDistance < oldDistance);
 
-        const oldDistance = getVerDistance(items[0], items[1]);
-        ReactTestUtils.Simulate.click(mountNode.querySelector('.next-btn'));
-        const newDistance = getVerDistance(items[0], items[1]);
-        assert(oldDistance === newDistance);
+            wrapper.unmount();
+        });
     });
 });

test/util/index.js

@@ -1,3 +1,6 @@
+import React from 'react';
+import ReactDOM from 'react-dom';
+
 const delay = time => new Promise(resolve => setTimeout(resolve, time));
 
 const render = element => {

types/form/index.d.ts

@@ -238,6 +238,13 @@ export interface ItemProps extends React.HTMLAttributes<HTMLElement>, CommonProp
      */
     useLabelForErrorMessage?: boolean;
 
+    /**
+     * 是否使用item的marginBottom空间来展示help
+     * @default false
+     * @version 1.26.37
+     */
+    preferMarginToDisplayHelp?: boolean;
+
     /**
      * 表示是否显示 label 后面的冒号
      */
@@ -530,6 +537,12 @@ export interface FormProps extends HTMLAttributesWeak, CommonProps {
      * 是否使用 label 替换校验信息的 name 字段
      */
     useLabelForErrorMessage?: boolean;
+    /**
+     * 是否使用item的marginBottom空间来展示help
+     * @default false
+     * @version 1.26.37
+     */
+    preferMarginToDisplayHelp?: boolean;
 }
 
 export default class Form extends React.Component<FormProps, any> {