Get References From Another Method In JavaScript / TypeScript Class

Question

I am trying to create a class for Input Validation using JavaScript.

For example, the ExampleValidators class I have created:

export class ExampleValidator {
    private args: any;
    private errors = [];
    constructor(argsz) {
        this.args = argsz;
    }

    public required(inputName: string, customErrorMessage: string) {
        if (this.hasErrors(inputName)) return this;

        if (this.args.controls[inputName].value === null) {
            customErrorMessage = customErrorMessage ? customErrorMessage : inputName + ' Is required';
            this.addErrors(inputName, customErrorMessage);
        }

        return this;
    }

    public message(message: string) {
        this.errors = [];
        return this.errors = [message]
    }

    private addErrors(inputName: string, errorMessage: string) {
        this.errors[inputName] = errorMessage;
    }

    private hasErrors(inputName: string) {
        const errors = this.errors[inputName];
        return typeof errors === 'undefined' ? false : true;
    }
}

After that I tried to use the class by using a message:

private isValid() {
        this.exampleValidator.required('loginDateFrom');
        this.exampleValidator.required('loginDateTo').message('An example message: 02');
        return this.exampleValidator.passes();
    }

But after being displayed, the error appears not in specific: required ('loginDateTo'), but changes the overall error that appears.

How do I know that using 'custom message' is from reference: required ('loginDateTo'), so that the 'custom error message' has no effect on: 'required (' loginDateFrom ')?

I have tried using:

this.exampleValidator ('loginDateTo'). message ('loginDateTo', 'Some Message').

or

this.exampleValidator ('loginDateTo', 'Some Message');

It works, but I just want to try to use custom messages as I said above:

this.exampleValidator ('loginDateTo'). message ('Some Message')

How do I get a reference from the previous method: 'required' in the method: 'message'?

Or is there another way?

Thank you in advance.

Jonas Wilms · Accepted Answer · 2019-05-18 10:27:14Z

As you validate the check on the require call already, a message can't be added afterwards. However you could only create a list of rules when calling require, then when passes() gets called valudate them. With that, require could return a reference to a Rule, and that can be modified before the Rule is applied:

  class Rule {
   public _message = "";
   constructor(public readonly name: string) {}
   message(msg) { this._message = msg; }

   validate(obj) {
    if(obj[this.name]) return null;
    // an error occurs:
    return this._message || `${this.name} is required`;
   }
}

class Validator {
  rules: Rule[] = [];

  require(name) {
    const rule = new Rule(name);
    this.rules.push(rule);
    return rule;
  }

  passes() {
    const errors = this.rules.map(it => it.validate(/*...*/)).filter(it => it);
   const isValid = !errors.length;
   //...
  }
 }

Collectives™ on Stack Overflow

Get References From Another Method In JavaScript / TypeScript Class

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related