1.0.3 • Public • Published


Tatabot, (from Arabic تثبت which means Validation or Checking ), is a JSON schema validator written with Immutability and Modularity in mind. And which does not follow json-schema.org standard rules, because we believe that schema syntax can be much simpler than that standard. And that's what we made in Tatabot.


const tatabot = require("tatabot");

const schema = {
  "*name": "string",
  email: "email",
  age: { type: "integer", min: 13 },
  role: { type: "enum", values: ["admin", "follower"] }

const user1 = { name: "Bot", email: "tatabot@mm.co", age: "31", role: "admin" };
const user2 = { email: "tatabot", age: 10, role: "guest" }

const validation1 = tatabot.validate(user1, schema);
// validation1: { 
//   isValid: true,
//   errors: [],
//   coersion: { name: "Bot", email: "tatabot@mm.co", age: 31, role: "admin" }
// }

const validation2 = tatabot.validate(user2, schema);
// validation2: { 
//   isValid: false,
//   errors: [ "name is required", "email is not valid email", "age should be greater than 13" ],
//   coersion: { email: "tatabot", age: 10 }
// }


As you can see, Tatabot never changes the original object you passed to validation. Instead it returns a coerced object.

This, makes your code much more predictable, thus less buggy.


The modularity of Tatabot makes customization possible, so you can add your own custom types and their validation.


npm i --save tatabot

Core Concept

The main function of Tatabot is validate. It takes 3 arguments and returns 3 values.

It takes the object to be validated, the schema, and some additional validation options. And it returns a boolean that set to true if the object is valid, a flat array containing all validation errors and an object with coerced values.

See the example above

In addition to object and schema validate function takes a third argument, containing validation settings:

  • keepAdditional: true|false, if set to true, additional properties in object that are not mentioned in schema, will not be removed.
  • noRequired: true|false, if set to true, required type will not be handled, this is useful when you are validating an object intended for update purpose and which does not need to include all properties.

Setting types

Each property must have at least one type, this type (or those types), can be set in different ways.

  • Direct string The shortest form is this one. Just put the type as string value. Eg:
      age: "integer"
  • Direct array Thanks to its modularity, Tatabot allows property to have multiple types. In order to set multiple types you must put those types in array. The most common case is required type. (Yes required is considered as a type in Tatabot).
      age: ["required", "integer"]
  • type property The ways of doing shown above are very convenient when you just want to set types, but in many cases, you'll find yourself wanting to set some other options to the prop. In those cases, you have to set types in the long format, using type property. Eg:
      age: { type: "integer", min: 10 }
    And of course, you can also set multiple types in array. Eg:
      age: { type: ["required","integer"], min: 10 }

Setting required

As we saw earlier, required is a type. So if you want a property to be required, just give it the required type. Eg:

  name: ["required","string"] 

InKey required

As an alternative, you can add * in the begining of the property name, to set it as required. Eg:

  "*name": "string" 


This is the list of predefined types in Tatabot and their options.



  • minLength: mininmum length of string
  • maxLength: maximum length of string


  name: {type: "string", minLength: 3, maxLength: 6}


This takes the exact same options as string type. The only difference is that this type coerces the value to upper case.


Same uppercase for lower case.


Checks if value is a valid email.


Checks if value is a valid url.


Checks if parseInt of value is not NaN.


  • min: mininmum value
  • max: maximum value
  • blockFloat: true|false, wether to block floats or to parse them to int. Default false.


Checks if parseFloat of value is not NaN.


  • min: mininmum value
  • max: maximum value


Checks if value is listed among values option.


  • values: list of allowed values


  role: {type: "enum", values: ["admin", "follower"]}


Check if value is a valid date. and coerces it to date object.

Tatabot uses dayjs for date validation and parsing.


  • format: the format of given date. see dayjs Doc
  • before: a function that should return a date (or dayjs instance). to check wether or not the given date is before it.
  • after: a function similar to before, but for after checking.


const schema = { createdAt: {
  type: "date",
  format: "DD-MM-YYYY",
  after: () => dayjs("20-20-2020", "DD-MM-YYYY")
const item = { createdAt: "20-06-2018" }
const {isValid, coersion, errors} = tatabot.validate(item, schema);
// isValid: false 
// errors: ["createdAt should be after 20-20-2020"]


Handles the value as plain object, according to its schema option.


  • schema: schema of object


  pet: {type: "object", schema: {
    name: "string",
    species: {type: "enum", values: ["dog", "cat"]}


Checks the validity of the array.


  • minItems: minimum length of array
  • maxItems: maximum length of array
  • itemOptions: schema of item


  children: {type: "array", maxItems: 10, itemOptions: "string"}
// Here, you'll have an array of strings that accepts 10 items as maximum


  children: {type: "array", maxItems: 10, itemOptions: {
    type: "object",
    schema: {name: "string", age: "integer"}
// Here, you'll have an array of objects that accepts 10 items as maximum

Custom Types

As we said, the modularity of Tatabot allows you to set your own custom types. Use addType function to add a custom type this takes 2 arguments, the type name and the processors.

Processors is an object that should contain 2 functions, coerce and validate.

coerce returns the coerced value.

validate returns an array of errors. This array should be empty if the value is valid.

These two processors take the same 2 arguments:

  • value: the value to be processed
  • options: an object containing the following properties:
    • key: the property name that is being processed
    • propOptions: the property options in the schema (minLength, max...)
    • settings: the settings passed to validate function

Let's say you want to add password type, that accepts only strings longer than 6 and coerces all chars to * (miming crypting).

You'll write that code:

tatabot.addType("password", {
  coerce: (value, options) => value.split("").map(() => "*").join(""),
  validate: (value) => value.length < 6 ? ["password too short"] : [],


npm i tatabot

DownloadsWeekly Downloads






Unpacked Size

29.5 kB

Total Files


Last publish


  • burawi