refactor: switch statement to detect property type

Author: HenryBrown0

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

@@ -12,13 +12,8 @@ const Components = require('../util/Components');
 const docsUrl = require('../util/docsUrl');
 const report = require('../util/report');
 
-function isFlowPropertyType(node) {
-  return node.type === 'ObjectTypeProperty';
-}
-
-function isTypeScriptPropertyType(node) {
-  return node.type === 'TSPropertySignature';
-}
+const FLOW_PROPERTY_TYPE = 'ObjectTypeProperty';
+const TYPESCRIPT_PROPERTY_TYPE = 'TSPropertySignature';
 
 function isCovariant(node) {
   return (node.variance && node.variance.kind === 'plus')
@@ -85,18 +80,12 @@ module.exports = {
               return;
             }
 
-            if (isTypeScriptPropertyType(prop.node)) {
-              if (!isReadonly(prop.node)) {
-                reportReadOnlyProp(prop, propName, (fixer) => (
-                  fixer.insertTextBefore(prop.node, 'readonly ')
-                ));
-              }
+            switch (prop.node.type) {
+              case FLOW_PROPERTY_TYPE:
+                if (isCovariant(prop.node)) {
+                  break;
+                }
 
-              return;
-            }
-
-            if (isFlowPropertyType(prop.node)) {
-              if (!isCovariant(prop.node)) {
                 reportReadOnlyProp(prop, propName, (fixer) => {
                   if (!prop.node.variance) {
                     // Insert covariance
@@ -106,7 +95,20 @@ module.exports = {
                   // Replace contravariance with covariance
                   return fixer.replaceText(prop.node.variance, '+');
                 });
-              }
+
+                break;
+              case TYPESCRIPT_PROPERTY_TYPE:
+                if (isReadonly(prop.node)) {
+                  break;
+                }
+
+                reportReadOnlyProp(prop, propName, (fixer) => (
+                  fixer.insertTextBefore(prop.node, 'readonly ')
+                ));
+
+                break;
+              default:
+                break;
             }
           });
         });