Merge pull request #1300 from gaearon/4.12.7

4.12.7

.prettierignore

@@ -9,4 +9,5 @@ babel.js
 index.js
 patch.js
 root.js
-test/hot/react-dom
+test/hot/react-dom
+coverage

README.md

@@ -67,6 +67,11 @@ There is only one condition for it - a non zero dependencies list.
 🔥 useEffect(effect, ["hot"]); // the simplest way to make hook reloadable
 ```
 
+**Plus**
+
+* any hook would be reloaded on a function body change. Enabled by default, controlled by `reloadHooksOnBodyChange` option.
+* you may configure RHL to reload any hook by setting `reloadLifeCycleHooks` option to true.
+
 **To disable hooks reloading** - set configuration option:
 
 ```js

src/configuration.js

@@ -11,9 +11,15 @@ const configuration = {
   // Allows SFC to be used, enables "intermediate" components used by Relay, should be disabled for Preact
   allowSFC: true,
 
-  // Allow hot reload of effect hooks
+  // Allow reload of effect hooks with non zero dependency list
   reloadHooks: true,
 
+  // Allow reload of mount effect hooks - zero deps
+  reloadLifeCycleHooks: false,
+
+  // Enables hook reload on hook body change
+  reloadHooksOnBodyChange: true,
+
   // Disable "hot-replacement-render"
   disableHotRenderer: false,
 

src/reactHotLoader.js

@@ -29,8 +29,24 @@ const forceSimpleSFC = { proxy: { pureSFC: true } };
 
 const hookWrapper = hook => {
   const wrappedHook = function(cb, deps) {
-    if (configuration.reloadHooks) {
-      return hook(cb, deps && deps.length > 0 ? [...deps, getHotGeneration()] : deps);
+    if (configuration.reloadHooks && deps) {
+      const inputs = [...deps];
+
+      // reload hooks which have changed string representation
+      if (configuration.reloadHooksOnBodyChange) {
+        inputs.push(String(cb));
+      }
+
+      if (
+        // reload hooks with dependencies
+        deps.length > 0 ||
+        // reload all hooks of option is set
+        (configuration.reloadLifeCycleHooks && deps.length === 0)
+      ) {
+        inputs.push(getHotGeneration());
+      }
+
+      return hook(cb, inputs);
     }
     return hook(cb, deps);
   };

src/reconciler/componentComparator.js

@@ -182,41 +182,45 @@ const compareComponents = (oldType, newType, setNewType, baseType) => {
 const knownPairs = new WeakMap();
 const emptyMap = new WeakMap();
 
+const getKnownPair = (oldType, newType) => {
+  const pair = knownPairs.get(oldType) || emptyMap;
+  return pair.get(newType);
+};
+
 export const hotComponentCompare = (oldType, preNewType, setNewType, baseType) => {
   const hotActive = hotComparisonOpen();
   const newType = configuration.integratedResolver ? resolveType(preNewType) : preNewType;
-  let result = oldType === newType;
 
-  if (!hotActive) {
-    return result;
-  }
+  // TODO: find out the root cause
+  // we could not use "fast result" here - go a full part to update a fiber.
+  // const knownType = getKnownPair(oldType, newType);
+  // if (knownType !== undefined) {
+  //   return knownType;
+  // }
 
-  if (
-    !isReloadableComponent(oldType) ||
-    !isReloadableComponent(newType) ||
-    isColdType(oldType) ||
-    isColdType(oldType) ||
-    !oldType ||
-    !newType ||
-    0
-  ) {
-    return result;
-  }
+  let result = oldType === newType;
 
-  // comparison should be active only if hot update window
-  // or it would merge components it shall not
   if (hotActive) {
+    // pre fail components which could not be merged
+    if (
+      !isReloadableComponent(oldType) ||
+      !isReloadableComponent(newType) ||
+      isColdType(oldType) ||
+      isColdType(oldType) ||
+      !oldType ||
+      !newType ||
+      0
+    ) {
+      return result;
+    }
+
     result = compareComponents(oldType, newType, setNewType, baseType);
     const pair = knownPairs.get(oldType) || new WeakMap();
     pair.set(newType, result);
     knownPairs.set(oldType, pair);
     return result;
   }
 
-  if (result) {
-    return result;
-  }
-
-  const pair = knownPairs.get(oldType) || emptyMap;
-  return pair.get(newType) || false;
+  // result - true if components are equal, or were "equal" at any point in the past
+  return result || getKnownPair(oldType, newType) || false;
 };

src/reconciler/resolver.js

@@ -12,17 +12,23 @@ import configuration, { internalConfiguration } from '../configuration';
 const shouldNotPatchComponent = type => isTypeBlacklisted(type);
 
 export function resolveType(type, options = {}) {
-  const element = { type };
-  if (isLazyType(element) || isMemoType(element) || isForwardType(element) || isContextType(element)) {
-    return getProxyByType(type) || type;
-  }
-
+  // fast return
   if (!isCompositeComponent(type) || isProxyType(type)) {
     return type;
   }
 
+  const element = { type };
+
+  // fast meta
+  if (typeof element === 'object') {
+    if (isLazyType(element) || isMemoType(element) || isForwardType(element) || isContextType(element)) {
+      return getProxyByType(type) || type;
+    }
+  }
+
   const existingProxy = getProxyByType(type);
 
+  // cold API
   if (shouldNotPatchComponent(type)) {
     return existingProxy ? existingProxy.getCurrent() : type;
   }