refactor: move out of class

lib/types.js

@@ -1252,28 +1252,44 @@ function generateProjectionIndexer(projectionFn) {
   };
 }
 
-function generateDefaultIndexer() {
-  this._dynamicBranches = null;
-  this._bucketIndices = {};
-  this.types.forEach(function (type, index) {
-    if (Type.isType(type, 'abstract', 'logical')) {
-      if (!this._dynamicBranches) {
-        this._dynamicBranches = [];
+function generateDefaultIndexer(types) {
+  const dynamicBranches = [];
+  const bucketIndices = {};
+
+  const getBranchIndex = (any, index) => {
+    let logicalBranches = dynamicBranches;
+    for (let i = 0, l = logicalBranches.length; i < l; i++) {
+      let branch = logicalBranches[i];
+      if (branch.type._check(any)) {
+        if (index === undefined) {
+          index = branch.index;
+        } else {
+          // More than one branch matches the value so we aren't guaranteed to
+          // infer the correct type. We throw rather than corrupt data. This can
+          // be fixed by "tightening" the logical types.
+          throw new Error('ambiguous conversion');
+        }
       }
-      this._dynamicBranches.push({index, type});
+    }
+    return index;
+  }
+
+  types.forEach(function (type, index) {
+    if (Type.isType(type, 'abstract', 'logical')) {
+      dynamicBranches.push({index, type});
     } else {
       let bucket = getTypeBucket(type);
-      if (this._bucketIndices[bucket] !== undefined) {
+      if (bucketIndices[bucket] !== undefined) {
         throw new Error(`ambiguous unwrapped union: ${j(this)}`);
       }
-      this._bucketIndices[bucket] = index;
+      bucketIndices[bucket] = index;
     }
   }, this);
   return (val) => {
-    let index = this._bucketIndices[getValueBucket(val)];
-    if (this._dynamicBranches) {
+    let index = bucketIndices[getValueBucket(val)];
+    if (dynamicBranches.length) {
       // Slower path, we must run the value through all branches.
-      index = this._getBranchIndex(val, index);
+      index = getBranchIndex(val, index);
     }
     return index;
   };
@@ -1310,30 +1326,12 @@ class UnwrappedUnionType extends UnionType {
       }
     }
     this._getIndex = _projectionFn
-      ? generateProjectionIndexer(projectionFn)
+      ? generateProjectionIndexer(_projectionFn)
       : generateDefaultIndexer.bind(this)(this.types);
 
     Object.freeze(this);
   }
 
-  _getBranchIndex (any, index) {
-    let logicalBranches = this._dynamicBranches;
-    for (let i = 0, l = logicalBranches.length; i < l; i++) {
-      let branch = logicalBranches[i];
-      if (branch.type._check(any)) {
-        if (index === undefined) {
-          index = branch.index;
-        } else {
-          // More than one branch matches the value so we aren't guaranteed to
-          // infer the correct type. We throw rather than corrupt data. This can
-          // be fixed by "tightening" the logical types.
-          throw new Error('ambiguous conversion');
-        }
-      }
-    }
-    return index;
-  }
-
   _check (val, flags, hook, path) {
     let index = this._getIndex(val);
     let b = index !== undefined;
@@ -1393,16 +1391,18 @@ class UnwrappedUnionType extends UnionType {
           // Using the `coerceBuffers` option can cause corruption and erroneous
           // failures with unwrapped unions (in rare cases when the union also
           // contains a record which matches a buffer's JSON representation).
-          if (isJsonBuffer(val) && this._bucketIndices.buffer !== undefined) {
-            index = this._bucketIndices.buffer;
-          } else {
-            index = this._getIndex(val);
+          if (isJsonBuffer(val)) {
+            let bufIndex = this.types.findIndex(t => getTypeBucket(t) === 'buffer');
+            if (bufIndex !== -1) {
+              index = bufIndex;
+            }
           }
+          index ??= this._getIndex(val);
           break;
         case 2:
           // Decoding from JSON, we must unwrap the value.
           if (val === null) {
-            index = this._bucketIndices['null'];
+            index = this._getIndex(null);
           } else if (typeof val === 'object') {
             let keys = Object.keys(val);
             if (keys.length === 1) {