KO Validation

Add validation to Knockout observables.

Install

bower install folke-ko-validation --save

Getting started

  // Imports the module with require.js
  var validation = require('folke-ko-validation');
  
  // Creates a new observable with two validators
  var value = validation.validableObservable()
      .addValidator(validator.isRequired)
      .addValidator(validator.hasMaxLength(8));
  
  value("way too long");
  
  // Displays an error message
  console.log(value.errorMessage());

Properties of a validableObservable

• errorMessage: a string observable with an error message or null if no error is found
• validating: a boolean that is true if there is any pending asynchronous validation
• addValidation : a method to add a new validator

Localization

The errorMessages object holds the error message and may be localized.

Validators

• isEmail: checks that it is an e-mail address
• isRequired: checks that the value is not null or empty
• hasMinLength(number): checks that the string has at least a given number of characters
• hasMaxLength(number): checks that the string has at most a given number of characters
• isInRange(min, max): checks that a number is between two values (included)
• validateService(service): the service is a function that takes a string in parameters and returns a ES6 promise with the error message
• areSame(observable): checks that it is the same value as another observable