Add keyPath and recursive parentNode

Readme.md

@@ -1430,7 +1430,7 @@ Then use this custom key in your JSON
 
 ### 19.5. <a name='Customerrorfunctions'></a>Custom error functions
 
-You can also add custom error functions at a granular level with access to `constraints`, `key` , `title`, `description`, `parentNode` and `typeHandler`
+You can also add custom error functions at a granular level with access to `constraints`, `key` , `keyPath`, `title`, `description`, `parentNode` and `typeHandler`
 
 ````js
   const message2 = {

src/error-message-handler.js

@@ -15,6 +15,7 @@ export class ErrorMessageHandler extends TypeMatcher {
     this.value = typeHandler.value; // raw type constraints
     this.constraints = typeHandler.constraints; // type constraints (possibly filtered)
     this.parentNode = typeHandler.parentNode;
+    this.keyPath = typeHandler.keyPath;
     this.type = typeHandler.type;
     this.description = typeHandler.description;
     this.title = typeHandler.title;
@@ -45,8 +46,15 @@ export class ErrorMessageHandler extends TypeMatcher {
   }
 
   validationErrorMessage(msgName) {
-    const { constraints, key, description, title, typeHandler, parentNode } =
-      this;
+    const {
+      constraints,
+      key,
+      description,
+      title,
+      typeHandler,
+      keyPath,
+      parentNode,
+    } = this;
     const errMsg = this.errMessageFor(msgName);
     return typeof errMsg === "function"
       ? errMsg(constraints, {
@@ -55,6 +63,7 @@ export class ErrorMessageHandler extends TypeMatcher {
           description,
           typeHandler,
           parentNode,
+          keyPath,
         })
       : errMsg;
   }

src/types/mixed/mixed.js

@@ -45,6 +45,25 @@ class YupMixed extends Base {
     this.base = this.getBase();
   }
 
+  get keyPath() {
+    this._keyPath = this._keyPath || this.calcKeyPath();
+    return this._keyPath;
+  }
+
+  calcKeyPath() {
+    let ctx = this;
+    let parentNode;
+    let keys = [];
+    while ((parentNode = ctx.parentNode)) {
+      if (!parentNode) {
+        break;
+      }
+      keys.push(parentNode.key);
+      ctx = ctx.parentNode;
+    }
+    return keys.join(".");
+  }
+
   get builder() {
     return this.entryHandler && this.entryHandler.builder;
   }

src/types/object/object.js

@@ -42,6 +42,7 @@ export class YupObject extends YupMixed {
       const parentNode = {
         key: this.key,
         ...this.value,
+        parentNode: this.parentNode,
       };
       const yupSchema = this.config.buildYup(schema, config, parentNode);
       this.base = yupSchema;