[Refactor] Components: use a closed-over WeakMap instead of a not-private property

Author: ljharb

lib/util/Components.js

@@ -45,12 +45,14 @@ function mergeUsedPropTypes(propsList, newPropsList) {
   return propsList.concat(propsToAdd);
 }
 
+const Lists = new WeakMap();
+
 /**
  * Components
  */
 class Components {
   constructor() {
-    this._list = {};
+    Lists.set(this, {});
   }
 
   /**
@@ -62,19 +64,20 @@ class Components {
    */
   add(node, confidence) {
     const id = getId(node);
-    if (this._list[id]) {
-      if (confidence === 0 || this._list[id].confidence === 0) {
-        this._list[id].confidence = 0;
+    const list = Lists.get(this);
+    if (list[id]) {
+      if (confidence === 0 || list[id].confidence === 0) {
+        list[id].confidence = 0;
       } else {
-        this._list[id].confidence = Math.max(this._list[id].confidence, confidence);
+        list[id].confidence = Math.max(list[id].confidence, confidence);
       }
-      return this._list[id];
+      return list[id];
     }
-    this._list[id] = {
+    list[id] = {
       node,
       confidence
     };
-    return this._list[id];
+    return list[id];
   }
 
   /**
@@ -85,8 +88,9 @@ class Components {
    */
   get(node) {
     const id = getId(node);
-    if (this._list[id] && this._list[id].confidence >= 1) {
-      return this._list[id];
+    const item = Lists.get(this)[id];
+    if (item && item.confidence >= 1) {
+      return item;
     }
     return null;
   }
@@ -98,13 +102,14 @@ class Components {
    * @param {Object} props Additional properties to add to the component.
    */
   set(node, props) {
-    let component = this._list[getId(node)];
+    const list = Lists.get(this);
+    let component = list[getId(node)];
     while (!component) {
       node = node.parent;
       if (!node) {
         return;
       }
-      component = this._list[getId(node)];
+      component = list[getId(node)];
     }
 
     Object.assign(
@@ -126,14 +131,15 @@ class Components {
    * @returns {Object} Components list
    */
   list() {
+    const thisList = Lists.get(this);
     const list = {};
     const usedPropTypes = {};
 
     // Find props used in components for which we are not confident
-    Object.keys(this._list).filter(i => this._list[i].confidence < 2).forEach((i) => {
+    Object.keys(thisList).filter(i => thisList[i].confidence < 2).forEach((i) => {
       let component = null;
       let node = null;
-      node = this._list[i].node;
+      node = thisList[i].node;
       while (!component && node.parent) {
         node = node.parent;
         // Stop moving up if we reach a decorator
@@ -143,7 +149,7 @@ class Components {
         component = this.get(node);
       }
       if (component) {
-        const newUsedProps = (this._list[i].usedPropTypes || []).filter(propType => !propType.node || propType.node.kind !== 'init');
+        const newUsedProps = (thisList[i].usedPropTypes || []).filter(propType => !propType.node || propType.node.kind !== 'init');
 
         const componentId = getId(component.node);
 
@@ -152,9 +158,9 @@ class Components {
     });
 
     // Assign used props in not confident components to the parent component
-    Object.keys(this._list).filter(j => this._list[j].confidence >= 2).forEach((j) => {
-      const id = getId(this._list[j].node);
-      list[j] = this._list[j];
+    Object.keys(thisList).filter(j => thisList[j].confidence >= 2).forEach((j) => {
+      const id = getId(thisList[j].node);
+      list[j] = thisList[j];
       if (usedPropTypes[id]) {
         list[j].usedPropTypes = mergeUsedPropTypes(list[j].usedPropTypes || [], usedPropTypes[id]);
       }
@@ -169,7 +175,8 @@ class Components {
    * @returns {Number} Components list length
    */
   length() {
-    return Object.keys(this._list).filter(i => this._list[i].confidence >= 2).length;
+    const list = Lists.get(this);
+    return Object.keys(list).filter(i => list[i].confidence >= 2).length;
   }
 }