Validation Error Format

[jerradpatch]

I am wanting to bind the validation error to my template with NG4, however given the current output of ValidationError[] I have to iterate to find the offender and then pull the message. I then have to bind the message to an object that is bound to the error for that field. I would be nice to get an object output instead of an array that could be bound to.

validationErrors: {
   <fieldName>: [{constraint: <constraintName>, message: <actualMessage>}],
   <anotherFieldName: [{...},{...}],
    ...
}

Where in the template I could bind to this result with angular4
<div *ngFor="let err of resultModel.email">
    {{err.constraint}}{{err.email}}
</div>
<input type="email" [(ngModel)]="model.email">

[jerradpatch]

something like this is what I was imagining.

export function validationErrorToObject(ve: ValidationError[]): ValidationObject {
    return ve.reduce((p, c:ValidationError) : ValidationObject => {
        if(!c.children || !c.children.length) {
            p[c.property] = {
                value: c.value,
                constraints: Object.keys(c.constraints)
                  .map(key=>{
                   return capitalize(c.constraints[key])+".\u00a0";
                  })
            }
        } else {
            p[c.property] = validationErrorToObject(c.children);
        }
        return p;
    }, {} as ValidationObject);
}

export interface ValidationObject {
    [key: string]:
      {value: string, constraints: string[] } | ValidationObject
}

export function capitalize(string) {
  return string.charAt(0).toUpperCase() + string.slice(1);
}

[st-clair-clarke]

I support your suggestion. This might be ideal for angular usage.

[NoNameProvided]

Just to be clear, so you want a structure like this:

// class definition
class Post {
  @IsString()
  title: string;

  @IsString()
  body: string;
	
  @ValidateNested()
  author: User
}

// validation result
{
  title: [{ constraint: 'isString', message: 'title must be a string.'}],
  body: [{ constraint: 'isString', message: 'body must be a string.'}],
  author: { 
    name: [{ constraint: 'isString', message: 'name must be a string.'}],
    age: [{ constraint: 'isInit', message: 'age must be an integer.'}],
  } 
}

[HonoluluHenk]

Much easier to handle!

Please do not forget that messages need translation and also need to include constraint parameters.
Maybe see #238 for a possible solution.