feat: add showConstraintMessages option to ValidationError.toString() (#1612)

Author: ahoisl

src/validation/ValidationError.ts

@@ -45,14 +45,20 @@ export class ValidationError {
    * @param shouldDecorate decorate the message with ANSI formatter escape codes for better readability
    * @param hasParent true when the error is a child of an another one
    * @param parentPath path as string to the parent of this property
+   * @param showConstraintMessages show constraint messages instead of constraint names
    */
-  toString(shouldDecorate: boolean = false, hasParent: boolean = false, parentPath: string = ``): string {
+  toString(
+    shouldDecorate: boolean = false,
+    hasParent: boolean = false,
+    parentPath: string = ``,
+    showConstraintMessages: boolean = false
+  ): string {
     const boldStart = shouldDecorate ? `\x1b[1m` : ``;
     const boldEnd = shouldDecorate ? `\x1b[22m` : ``;
+    const constraintsToString = () =>
+      (showConstraintMessages ? Object.values : Object.keys)(this.constraints ?? {}).join(`, `);
     const propConstraintFailed = (propertyName: string): string =>
-      ` - property ${boldStart}${parentPath}${propertyName}${boldEnd} has failed the following constraints: ${boldStart}${Object.keys(
-        this.constraints
-      ).join(`, `)}${boldEnd} \n`;
+      ` - property ${boldStart}${parentPath}${propertyName}${boldEnd} has failed the following constraints: ${boldStart}${constraintsToString()}${boldEnd} \n`;
 
     if (!hasParent) {
       return (
@@ -61,7 +67,9 @@ export class ValidationError {
         }${boldEnd} has failed the validation:\n` +
         (this.constraints ? propConstraintFailed(this.property) : ``) +
         (this.children
-          ? this.children.map(childError => childError.toString(shouldDecorate, true, this.property)).join(``)
+          ? this.children
+              .map(childError => childError.toString(shouldDecorate, true, this.property, showConstraintMessages))
+              .join(``)
           : ``)
       );
     } else {
@@ -75,7 +83,9 @@ export class ValidationError {
       } else {
         return this.children
           ? this.children
-              .map(childError => childError.toString(shouldDecorate, true, `${parentPath}${formattedProperty}`))
+              .map(childError =>
+                childError.toString(shouldDecorate, true, `${parentPath}${formattedProperty}`, showConstraintMessages)
+              )
               .join(``)
           : ``;
       }

src/validation/ValidationExecutor.ts

@@ -45,9 +45,9 @@ export class ValidationExecutor {
      */
     if (!this.metadataStorage.hasValidationMetaData && this.validatorOptions?.enableDebugMessages === true) {
       console.warn(
-        `No validation metadata found. No validation will be  performed. There are multiple possible reasons:\n` + 
-        `  - There may be multiple class-validator versions installed. You will need to flatten your dependencies to fix the issue.\n` + 
-        `  - This validation runs before any file with validation decorator was parsed by NodeJS.`
+        `No validation metadata found. No validation will be  performed. There are multiple possible reasons:\n` +
+          `  - There may be multiple class-validator versions installed. You will need to flatten your dependencies to fix the issue.\n` +
+          `  - This validation runs before any file with validation decorator was parsed by NodeJS.`
       );
     }
 

test/functional/validation-error.spec.ts

@@ -49,6 +49,7 @@ describe('ValidationError', () => {
     }
 
     const validationErrors = await validator.validate(new RootClass());
+    expect(validationErrors).toHaveLength(3);
     expect(validationErrors[0].toString()).toEqual(
       'An instance of RootClass has failed the validation:\n' +
         ' - property title has failed the following constraints: minLength, isString \n'
@@ -67,5 +68,23 @@ describe('ValidationError', () => {
         ' - property nestedArr[1].name has failed the following constraints: isString \n' +
         ' - property nestedArr[1].url has failed the following constraints: isUrl \n'
     );
+    expect(validationErrors[0].toString(undefined, undefined, undefined, true)).toEqual(
+      'An instance of RootClass has failed the validation:\n' +
+        ' - property title has failed the following constraints: title must be longer than or equal to 15 characters, title must be a string \n'
+    );
+    expect(validationErrors[1].toString(undefined, undefined, undefined, true)).toEqual(
+      'An instance of RootClass has failed the validation:\n' +
+        ' - property nestedObj.name has failed the following constraints: name must be a string \n' +
+        ' - property nestedObj.url has failed the following constraints: url must be a URL address \n' +
+        ' - property nestedObj.insideNested.name has failed the following constraints: name must be a string \n' +
+        ' - property nestedObj.insideNested.url has failed the following constraints: url must be a URL address \n'
+    );
+    expect(validationErrors[2].toString(undefined, undefined, undefined, true)).toEqual(
+      'An instance of RootClass has failed the validation:\n' +
+        ' - property nestedArr[0].name has failed the following constraints: name must be a string \n' +
+        ' - property nestedArr[0].url has failed the following constraints: url must be a URL address \n' +
+        ' - property nestedArr[1].name has failed the following constraints: name must be a string \n' +
+        ' - property nestedArr[1].url has failed the following constraints: url must be a URL address \n'
+    );
   });
 });