short-circuit childrenOnLine finder when a child is found

Author: TSMMark

lib/rules/jsx-one-element-per-line.js

@@ -39,6 +39,8 @@ module.exports = {
 
         const openingElementEndLine = node.loc.end.line;
 
+        // TODO: Just check if my parent opening tag is on the same line as me.
+
         // Children
         if (node.parent.children.length) {
           const childrenOnLine = [];
@@ -55,11 +57,11 @@ module.exports = {
             return;
           }
 
-          childrenOnLine.forEach(elementInLine => {
+          childrenOnLine.forEach(childOnLine => {
             context.report({
-              node: elementInLine,
-              message: `Opening tag for Element \`${elementInLine.openingElement.name.name}\` must be placed on a new line`,
-              fix: generateFixFunction(elementInLine)
+              node: childOnLine,
+              message: `Opening tag for Element \`${childOnLine.openingElement.name.name}\` must be placed on a new line`,
+              fix: generateFixFunction(childOnLine)
             });
           });
         }
@@ -85,26 +87,22 @@ module.exports = {
           return;
         }
 
-        const childrenOnLine = [];
         const closingElementStartLine = node.loc.end.line;
 
-        node.parent.children.forEach(childNode => {
-          const reportableLines = [childNode.openingElement, childNode.closingElement].reduce((lines, el) => {
+        const anyChildrenOnLine = node.parent.children.some(child => {
+          const reportableLines = [child.openingElement, child.closingElement].reduce((lines, el) => {
             if (!el) {
               return lines;
             }
 
             return lines.concat([el.loc.start.line, el.loc.end.line]);
           }, []);
 
-          if (reportableLines.indexOf(closingElementStartLine) === -1) {
-            return;
-          }
 
-          childrenOnLine.push(childNode);
+          return reportableLines.indexOf(closingElementStartLine) !== -1;
         });
 
-        if (!childrenOnLine.length) {
+        if (!anyChildrenOnLine) {
           return;
         }
 

tests/lib/rules/jsx-one-element-per-line.js

@@ -258,5 +258,21 @@ ruleTester.run('jsx-max-elements-per-line', rule, {
     ].join('\n'),
     errors: [{message: 'Opening tag for Element `Bar` must be placed on a new line'}],
     parserOptions: parserOptions
+  }, {
+    code: [
+      '<App>',
+      '  <Foo>',
+      '    <Bar /></Foo>',
+      '</App>'
+    ].join('\n'),
+    output: [
+      '<App>',
+      '  <Foo>',
+      '    <Bar />',
+      '</Foo>',
+      '</App>'
+    ].join('\n'),
+    errors: [{message: 'Closing tag for Element `Foo` must be placed on a new line'}],
+    parserOptions: parserOptions
   }]
 });