Merge pull request #162 from remarkablemark/feat/option-trim

feat: add option `trim`

README.md

@@ -252,6 +252,32 @@ See [htmlparser2 options](https://github.com/fb55/htmlparser2/wiki/Parser-option
 
 > **Warning**: By overriding htmlparser2 options, there's a chance of breaking universal rendering. Do this at your own risk.
 
+### trim
+
+Normally, whitespace is preserved:
+
+```js
+parse('<br>\n'); // [React.createElement('br'), '\n']
+```
+
+By enabling the `trim` option, whitespace text nodes will be skipped:
+
+```js
+parse('<br>\n', { trim: true }); // React.createElement('br')
+```
+
+This addresses the warning:
+
+```
+Warning: validateDOMNesting(...): Whitespace text nodes cannot appear as a child of <table>. Make sure you don't have any extra whitespace between tags on each line of your source code.
+```
+
+However, this option may strip out intentional whitespace:
+
+```js
+parse('<p> </p>', { trim: true }); // React.createElement('p')
+```
+
 ## FAQ
 
 #### Is this library XSS safe?
@@ -288,6 +314,10 @@ parse('<div /><div />'); // returns single element instead of array of elements
 
 See [#158](https://github.com/remarkablemark/html-react-parser/issues/158).
 
+#### I get "Warning: validateDOMNesting(...): Whitespace text nodes cannot appear as a child of table."
+
+Enable the [trim](https://github.com/remarkablemark/html-react-parser#trim) option. See [#155](https://github.com/remarkablemark/html-react-parser/issues/155).
+
 ## Benchmarks
 
 ```sh

index.d.ts

@@ -21,6 +21,8 @@ export interface HTMLReactParserOptions {
   replace?: (
     domNode: DomElement
   ) => JSX.Element | object | void | undefined | null | false;
+
+  trim?: boolean;
 }
 
 /**

lib/dom-to-react.js

@@ -24,6 +24,8 @@ function domToReact(nodes, options) {
   var replaceElement;
   var props;
   var children;
+  var data;
+  var trim = options.trim;
 
   for (var i = 0, len = nodes.length; i < len; i++) {
     node = nodes[i];
@@ -33,7 +35,7 @@ function domToReact(nodes, options) {
       replaceElement = options.replace(node);
 
       if (isValidElement(replaceElement)) {
-        // specify a "key" prop if element has siblings
+        // set "key" prop for sibling elements
         // https://fb.me/react-warning-keys
         if (len > 1) {
           replaceElement = cloneElement(replaceElement, {
@@ -46,45 +48,54 @@ function domToReact(nodes, options) {
     }
 
     if (node.type === 'text') {
-      result.push(node.data);
+      // if trim option is enabled, skip whitespace text nodes
+      if (trim) {
+        data = node.data.trim();
+        if (data) {
+          result.push(node.data);
+        }
+      } else {
+        result.push(node.data);
+      }
       continue;
     }
 
     props = node.attribs;
     if (!shouldPassAttributesUnaltered(node)) {
-      // update values
       props = attributesToProps(node.attribs);
     }
 
     children = null;
 
-    // node type for <script> is "script"
-    // node type for <style> is "style"
-    if (node.type === 'script' || node.type === 'style') {
-      // prevent text in <script> or <style> from being escaped
-      // https://facebook.github.io/react/tips/dangerously-set-inner-html.html
-      if (node.children[0]) {
-        props.dangerouslySetInnerHTML = {
-          __html: node.children[0].data
-        };
-      }
-    } else if (node.type === 'tag') {
-      // setting textarea value in children is an antipattern in React
-      // https://reactjs.org/docs/forms.html#the-textarea-tag
-      if (node.name === 'textarea' && node.children[0]) {
-        props.defaultValue = node.children[0].data;
-
-        // continue recursion of creating React elements (if applicable)
-      } else if (node.children && node.children.length) {
-        children = domToReact(node.children, options);
-      }
+    switch (node.type) {
+      case 'script':
+      case 'style':
+        // prevent text in <script> or <style> from being escaped
+        // https://reactjs.org/docs/dom-elements.html#dangerouslysetinnerhtml
+        if (node.children[0]) {
+          props.dangerouslySetInnerHTML = {
+            __html: node.children[0].data
+          };
+        }
+        break;
+
+      case 'tag':
+        // setting textarea value in children is an antipattern in React
+        // https://reactjs.org/docs/forms.html#the-textarea-tag
+        if (node.name === 'textarea' && node.children[0]) {
+          props.defaultValue = node.children[0].data;
+        } else if (node.children && node.children.length) {
+          // continue recursion of creating React elements (if applicable)
+          children = domToReact(node.children, options);
+        }
+        break;
 
       // skip all other cases (e.g., comment)
-    } else {
-      continue;
+      default:
+        continue;
     }
 
-    // specify a "key" prop if element has siblings
+    // set "key" prop for sibling elements
     // https://fb.me/react-warning-keys
     if (len > 1) {
       props.key = i;
@@ -97,6 +108,8 @@ function domToReact(nodes, options) {
 }
 
 /**
+ * Determines whether attributes should be altered or not.
+ *
  * @param {React.ReactElement} node
  * @return {Boolean}
  */

test/html-to-react.js

@@ -152,5 +152,27 @@ describe('HTML to React', () => {
         );
       });
     });
+
+    describe('trim', () => {
+      it('preserves whitespace text nodes when disabled (default)', () => {
+        const html = `<table>
+  <tbody>
+  </tbody>
+</table>`;
+        const reactElement = parse(html);
+        assert.strictEqual(render(reactElement), html);
+      });
+
+      it('removes whitespace text nodes when enabled', () => {
+        const html = `<table>
+      <tbody><tr><td> text </td><td> </td>\t</tr>\r</tbody>\n</table>`;
+        const options = { trim: true };
+        const reactElement = parse(html, options);
+        assert.strictEqual(
+          render(reactElement),
+          '<table><tbody><tr><td> text </td><td></td></tr></tbody></table>'
+        );
+      });
+    });
   });
 });

test/types/index.test.tsx

@@ -72,6 +72,9 @@ parse('<p/><p/>', {
   }
 });
 
+// $ExpectType Element | Element[]
+parse('\t<p>text \r</p>\n', { trim: true });
+
 // $ExpectType DomElement[]
 const domNodes = htmlToDOM('<div>text</div>');
 

test/types/lib/dom-to-react.test.tsx

@@ -38,3 +38,6 @@ domToReact(htmlToDOM('<a id="header" href="#">Heading</a>'), {
     }
   }
 });
+
+// $ExpectType Element | Element[]
+domToReact(htmlToDOM('\t<p>text \r</p>\n'), { trim: true });