At the moment I've got this:

const checkText = (t) => ({
    isNotEmpty: function () {
      if (t.length === 0) {
        throw new Error("isNotEmpty false");
      }
      return this;
    },
    isEmail: function () {
      const emailRegex = /^\w ([\.-]?\w )*@\w ([\.-]?\w )*(\.\w{1,20}) $/;
      if (!emailRegex.test(t)) {
        throw new Error("isEmail false");
      }
      return this;
    }
};

Using a try catch, if the text is not valid, an error is thrown and handled this way:

const isFieldValid = (email) => {
  try {
    const v = checkText(email)
      .isNotEmpty()
      .isEmail();
    if (v) {
      return true;
    }
  } catch (error) {
    return false;
  }
};

The goal is to short and clean the code, to avoiding the try catch, to have the final call in one line like this:

const isFieldValid = checkText('valid text').isNotEmpty().isEmail(); // one line

PS: I know there are library out there for validation. The code is an example.

CodePudding user response：

class CheckText {
  constructor(t) {
    this.t = t;
    this.valid = true;
  }
  isNotEmpty() {
    this.valid &&= this.t.length>0;
    return this;
  }
  isEmail() {
    this.valid &&= CheckText.emailRegex.test(this.t);
    return this;
  }
  static emailRegex = /^\w ([\.-]?\w )*@\w ([\.-]?\w )*(\.\w{1,20}) $/;
}

const isFieldValid = new CheckText('[email protected]').isNotEmpty().isEmail().valid;
console.log(isFieldValid);

However, I'd prefer to do it like this:

const emailRegex = /^\w ([\.-]?\w )*@\w ([\.-]?\w )*(\.\w{1,20}) $/;
const isNotEmpty = t => t.length>0;
const isEmail = t => emailRegex.test(t);
const validate = (t, validators) => validators.every(v=>v(t));
console.log(validate('[email protected]', [isNotEmpty, isEmail]));
console.log(validate('testexample.com',  [isNotEmpty, isEmail]));
console.log(validate('',                 [isNotEmpty, isEmail]));