validator-experimental-decorators/src/main.ts

A LIGHTWEIGHT TYPESCRIPT/JAVASCRIPT VALIDATOR

//VALIDATOR OF METHOD AND PARAMETER

export default class Validator {
  //Length Validator
  Length(minLength: number, maxLength: number) {
    return function (
      target: any,
      propertyKey: string,
      descriptor: PropertyDescriptor
    ) {
      const originalData = descriptor.value;

      descriptor.value = function (...args: any[]) {
        args.forEach((arg: string) => {
          if (arg.length < minLength || arg.length > maxLength) {
            throw new Error("Validation error!");
          }
        });
        return originalData.apply(this, args);
      };
      return descriptor;
    };
  }

  //Negative value validator
  validateNegativeNumber(
    target: any,
    propertyKey: string,
    descriptor: PropertyDescriptor
  ) {
    const originalData = descriptor.value;

    descriptor.value = function (...args: any[]) {
      const parameterValue = args[0];

      if (typeof parameterValue !== "number" || parameterValue >= 0) {
        throw new Error("Invalid parameter value. Expected a negative number");
      }

      return originalData.apply(this, args);
    };
  }

  validatePositiveNumber(
    target: any,
    propertyKey: string,
    descriptor: PropertyDescriptor
  ) {
    const originalData = descriptor.value;

    descriptor.value = function (...args: any[]) {
      const parameterValue = args[0];

      if (typeof parameterValue !== "number" || parameterValue <= 0) {
        throw new Error("Invalid parameter value. Expected a positive number");
      }

      return originalData.apply(this, args);
    };
  }

  isEmail(target: any, propertyKey: string, descriptor: PropertyDescriptor) {
    const originalData = descriptor.value;

    descriptor.value = function (...args: any[]) {
      const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
      const userInput = args[0];

      if (!emailRegex.test(userInput)) {
        throw new Error("invalid mail");
      }
      return originalData.apply(this, args);
    };
    return descriptor;
  }

  isValidPassword(
    target: any,
    propertyKey: string,
    descriptor: PropertyDescriptor
  ) {
    const originalData = descriptor.value;

    descriptor.value = function (...args: any[]) {
      const passwordRegex =
        /^(?=.*[0-9])(?=.*[!@#$%^&*])[a-zA-Z0-9!@#$%^&*]{6,16}$/;
      const userInput = args[0];

      if (passwordRegex.test(userInput)) {
        throw new Error("Invalid password");
      }
      return originalData.apply(this, args);
    };
    return descriptor;
  }
}