Reduce memory allocation in rules and utils

lib/rules/boolean-prop-naming.js

@@ -5,6 +5,7 @@
 
 'use strict';
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const propsUtil = require('../util/props');
 const docsUrl = require('../util/docsUrl');
@@ -173,17 +174,17 @@ module.exports = {
      * @param {Function} addInvalidProp callback to run for each error
      */
     function runCheck(proptypes, addInvalidProp) {
-      proptypes = proptypes || [];
-
-      proptypes.forEach((prop) => {
-        if (config.validateNested && nestedPropTypes(prop)) {
-          runCheck(prop.value.arguments[0].properties, addInvalidProp);
-          return;
-        }
-        if (flowCheck(prop) || regularCheck(prop) || tsCheck(prop)) {
-          addInvalidProp(prop);
-        }
-      });
+      if (proptypes && proptypes.length > 0) {
+        proptypes.forEach((prop) => {
+          if (config.validateNested && nestedPropTypes(prop)) {
+            runCheck(prop.value.arguments[0].properties, addInvalidProp);
+            return;
+          }
+          if (flowCheck(prop) || regularCheck(prop) || tsCheck(prop)) {
+            addInvalidProp(prop);
+          }
+        });
+      }
     }
 
     /**
@@ -312,18 +313,18 @@ module.exports = {
         }
 
         const list = components.list();
-        Object.keys(list).forEach((component) => {
+        values(list).forEach((component) => {
           // If this is a functional component that uses a global type, check it
           if (
             (
-              list[component].node.type === 'FunctionDeclaration'
-              || list[component].node.type === 'ArrowFunctionExpression'
+              component.node.type === 'FunctionDeclaration'
+              || component.node.type === 'ArrowFunctionExpression'
             )
-            && list[component].node.params
-            && list[component].node.params.length
-            && list[component].node.params[0].typeAnnotation
+            && component.node.params
+            && component.node.params.length
+            && component.node.params[0].typeAnnotation
           ) {
-            const typeNode = list[component].node.params[0].typeAnnotation;
+            const typeNode = component.node.params[0].typeAnnotation;
             const annotation = typeNode.typeAnnotation;
             let propType;
             if (annotation.type === 'GenericTypeAnnotation') {
@@ -336,14 +337,14 @@ module.exports = {
 
             if (propType) {
               validatePropNaming(
-                list[component].node,
+                component.node,
                 propType.properties || propType.members
               );
             }
           }
 
-          if (list[component].invalidProps && list[component].invalidProps.length > 0) {
-            reportInvalidNaming(list[component]);
+          if (component.invalidProps && component.invalidProps.length > 0) {
+            reportInvalidNaming(component);
           }
         });
 

lib/rules/default-props-match-prop-types.js

@@ -6,6 +6,7 @@
 
 'use strict';
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -93,10 +94,10 @@ module.exports = {
         const list = components.list();
 
         // If no defaultProps could be found, we don't report anything.
-        Object.keys(list).filter((component) => list[component].defaultProps).forEach((component) => {
+        values(list).filter((component) => component.defaultProps).forEach((component) => {
           reportInvalidDefaultProps(
-            list[component].declaredPropTypes,
-            list[component].defaultProps || {}
+            component.declaredPropTypes,
+            component.defaultProps || {}
           );
         });
       }

lib/rules/display-name.js

@@ -5,6 +5,7 @@
 
 'use strict';
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const astUtil = require('../util/ast');
 const docsUrl = require('../util/docsUrl');
@@ -229,9 +230,10 @@ module.exports = {
       'Program:exit'() {
         const list = components.list();
         // Report missing display name for all components
-        Object.keys(list).filter((component) => !list[component].hasDisplayName).forEach((component) => {
-          reportMissingDisplayName(list[component]);
-        });
+        values(list).filter((component) => !component.hasDisplayName)
+          .forEach((component) => {
+            reportMissingDisplayName(component);
+          });
       }
     };
   })

lib/rules/function-component-definition.js

@@ -5,6 +5,7 @@
 
 'use strict';
 
+const entries = require('object.entries');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -13,8 +14,8 @@ const docsUrl = require('../util/docsUrl');
 // ------------------------------------------------------------------------------
 
 function buildFunction(template, parts) {
-  return Object.keys(parts)
-    .reduce((acc, key) => acc.replace(`{${key}}`, parts[key] || ''), template);
+  return entries(parts)
+    .reduce((acc, entry) => acc.replace(`{${entry[0]}}`, entry[1] || ''), template);
 }
 
 const NAMED_FUNCTION_TEMPLATES = {

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

@@ -5,6 +5,8 @@
 
 'use strict';
 
+const entries = require('object.entries');
+const values = require('object.values');
 const docsUrl = require('../util/docsUrl');
 const jsxUtil = require('../util/jsx');
 
@@ -123,12 +125,14 @@ module.exports = {
         }
       });
 
-      Object.keys(childrenGroupedByLine).forEach((_line) => {
-        const line = parseInt(_line, 10);
+      entries(childrenGroupedByLine).forEach((lineEntry) => {
+        const lineKey = lineEntry[0];
+        const lineValue = lineEntry[1];
+        const line = parseInt(lineKey, 10);
         const firstIndex = 0;
-        const lastIndex = childrenGroupedByLine[line].length - 1;
+        const lastIndex = lineValue.length - 1;
 
-        childrenGroupedByLine[line].forEach((child, i) => {
+        lineValue.forEach((child, i) => {
           let prevChild;
           let nextChild;
 
@@ -137,7 +141,7 @@ module.exports = {
               prevChild = openingElement;
             }
           } else {
-            prevChild = childrenGroupedByLine[line][i - 1];
+            prevChild = lineValue[i - 1];
           }
 
           if (i === lastIndex) {
@@ -196,9 +200,7 @@ module.exports = {
         });
       });
 
-      Object.keys(fixDetailsByNode).forEach((key) => {
-        const details = fixDetailsByNode[key];
-
+      values(fixDetailsByNode).forEach((details) => {
         const nodeToReport = details.node;
         const descriptor = details.descriptor;
         const source = details.source.replace(/(^ +| +(?=\n)*$)/g, '');

lib/rules/no-direct-mutation-state.js

@@ -6,6 +6,7 @@
 
 'use strict';
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -140,9 +141,9 @@ module.exports = {
       'Program:exit'() {
         const list = components.list();
 
-        Object.keys(list).forEach((key) => {
-          if (!isValid(list[key])) {
-            reportMutations(list[key]);
+        values(list).forEach((val) => {
+          if (!isValid(val)) {
+            reportMutations(val);
           }
         });
       }

lib/rules/no-multi-comp.js

@@ -5,6 +5,7 @@
 
 'use strict';
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -67,10 +68,10 @@ module.exports = {
 
         const list = components.list();
 
-        Object.keys(list).filter((component) => !isIgnored(list[component])).forEach((component, i) => {
+        values(list).filter((component) => !isIgnored(component)).forEach((component, i) => {
           if (i >= 1) {
             context.report({
-              node: list[component].node,
+              node: component.node,
               messageId: 'onlyOneComponent'
             });
           }

lib/rules/no-set-state.js

@@ -5,6 +5,7 @@
 
 'use strict';
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -79,8 +80,8 @@ module.exports = {
 
       'Program:exit'() {
         const list = components.list();
-        Object.keys(list).filter((component) => !isValid(list[component])).forEach((component) => {
-          reportSetStateUsages(list[component]);
+        values(list).filter((component) => !isValid(component)).forEach((component) => {
+          reportSetStateUsages(component);
         });
       }
     };

lib/rules/no-unused-prop-types.js

@@ -8,6 +8,7 @@
 // As for exceptions for props.children or props.className (and alike) look at
 // https://github.com/yannickcr/eslint-plugin-react/issues/7
 
+const values = require('object.values');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -111,8 +112,7 @@ module.exports = {
         return;
       }
 
-      Object.keys(props || {}).forEach((key) => {
-        const prop = props[key];
+      values(props || {}).forEach((prop) => {
         // Skip props that check instances
         if (prop === true) {
           return;
@@ -159,11 +159,11 @@ module.exports = {
       'Program:exit'() {
         const list = components.list();
         // Report undeclared proptypes for all classes
-        Object.keys(list).filter((component) => mustBeValidated(list[component])).forEach((component) => {
-          if (!mustBeValidated(list[component])) {
+        values(list).filter((component) => mustBeValidated(component)).forEach((component) => {
+          if (!mustBeValidated(component)) {
             return;
           }
-          reportUnusedPropTypes(list[component]);
+          reportUnusedPropTypes(component);
         });
       }
     };

lib/rules/prefer-read-only-props.js

@@ -5,6 +5,8 @@
 
 'use strict';
 
+const entries = require('object.entries');
+const values = require('object.values');
 const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 
@@ -16,6 +18,33 @@ function isCovariant(node) {
   return (node.variance && (node.variance.kind === 'plus')) || (node.parent.parent.parent.id && (node.parent.parent.parent.id.name === '$ReadOnly'));
 }
 
+const reportPropTypeWithContext = (context) => (propEntry) => {
+  const propName = propEntry[0];
+  const prop = propEntry[1];
+  if (!isFlowPropertyType(prop.node)) {
+    return;
+  }
+
+  if (!isCovariant(prop.node)) {
+    context.report({
+      node: prop.node,
+      messageId: 'readOnlyProp',
+      data: {
+        name: propName
+      },
+      fix: (fixer) => {
+        if (!prop.node.variance) {
+          // Insert covariance
+          return fixer.insertTextBefore(prop.node, '+');
+        }
+
+        // Replace contravariance with covariance
+        return fixer.replaceText(prop.node.variance, '+');
+      }
+    });
+  }
+};
+
 // ------------------------------------------------------------------------------
 // Rule Definition
 // ------------------------------------------------------------------------------
@@ -41,39 +70,14 @@ module.exports = {
     'Program:exit'() {
       const list = components.list();
 
-      Object.keys(list).forEach((key) => {
-        const component = list[key];
+      const reportPropType = reportPropTypeWithContext(context);
 
+      values(list).forEach((component) => {
         if (!component.declaredPropTypes) {
           return;
         }
 
-        Object.keys(component.declaredPropTypes).forEach((propName) => {
-          const prop = component.declaredPropTypes[propName];
-
-          if (!isFlowPropertyType(prop.node)) {
-            return;
-          }
-
-          if (!isCovariant(prop.node)) {
-            context.report({
-              node: prop.node,
-              messageId: 'readOnlyProp',
-              data: {
-                name: propName
-              },
-              fix: (fixer) => {
-                if (!prop.node.variance) {
-                  // Insert covariance
-                  return fixer.insertTextBefore(prop.node, '+');
-                }
-
-                // Replace contravariance with covariance
-                return fixer.replaceText(prop.node.variance, '+');
-              }
-            });
-          }
-        });
+        entries(component.declaredPropTypes).forEach(reportPropType);
       });
     }
   }))