Add condition to errors, no tests yet

src/base.ts

@@ -1,4 +1,5 @@
 import { ReadonlyContext } from './context';
+import { ContextItem } from './context-items';
 
 export interface Request {
   [k: string]: any;
@@ -38,6 +39,7 @@ export type ValidationError =
       // These are optional so places don't need to define them, but can reference them
       location?: undefined;
       value?: undefined;
+      condition?: ContextItem;
     }
   | {
       location: Location;
@@ -46,6 +48,7 @@ export type ValidationError =
       msg: any;
       // This is optional so places don't need to define it, but can reference it
       nestedErrors?: unknown[];
+      condition?: ContextItem;
     };
 
 // Not using Symbol because of #813

src/context-items/custom-validation.ts

@@ -17,14 +17,19 @@ export class CustomValidation implements ContextItem {
       // A promise that was resolved only adds an error if negated.
       // Otherwise it always suceeds
       if ((!isPromise && failed) || (isPromise && this.negated)) {
-        context.addError(this.message, value, meta);
+        context.addError(this.message, value, meta, this);
       }
     } catch (err) {
       if (this.negated) {
         return;
       }
 
-      context.addError(this.message || (err instanceof Error ? err.message : err), value, meta);
+      context.addError(
+        this.message || (err instanceof Error ? err.message : err),
+        value,
+        meta,
+        this,
+      );
     }
   }
 }

src/context-items/standard-validation.ts

@@ -15,7 +15,7 @@ export class StandardValidation implements ContextItem {
   async run(context: Context, value: any, meta: Meta) {
     const result = this.validator(toString(value), ...this.options);
     if (this.negated ? result : !result) {
-      context.addError(this.message, value, meta);
+      context.addError(this.message, value, meta, this);
     }
   }
 }

src/context.ts

@@ -72,23 +72,32 @@ export class Context {
     instance.value = value;
   }
 
-  addError(message: any, value: any, meta: Meta): void;
+  addError(message: any, value: any, meta: Meta, condition: ContextItem): void;
   addError(message: any, nestedErrors: ValidationError[]): void;
-  addError(message: any, valueOrNestedErrors: any, meta?: Meta) {
+  addError(message: any, valueOrNestedErrors: any, meta?: Meta, condition?: ContextItem) {
     const msg = message || this.message || 'Invalid value';
+    let obj: ValidationError;
     if (meta) {
-      this._errors.push({
+      obj = {
         value: valueOrNestedErrors,
         msg: typeof msg === 'function' ? msg(valueOrNestedErrors, meta) : msg,
         param: meta.path,
         location: meta.location,
-      });
+      };
+      if (condition) {
+        Object.defineProperty(obj, 'condition', { value: condition });
+      }
+      this._errors.push(obj);
     } else {
-      this._errors.push({
+      obj = {
         msg,
         param: '_error',
         nestedErrors: valueOrNestedErrors,
-      });
+      };
+      if (condition) {
+        Object.defineProperty(obj, 'condition', { value: condition });
+      }
+      this._errors.push(obj);
     }
   }
 }