SimpleJsonValidator

Json Validator for NodeJS with simple ruby-like syntax

Installation

You can install this library using npm:

npm i --save simplejsonvalidator

Usage

First, you need to create a new JsonValidator instance calling to the exported function:

const jsonValidator = require('simplejsonvalidator');
const validator = jsonValidator();

Then, you can create validators using the 'create' method, which accepts a callback and the validator name

validator.create(t => ({
  user: t.string.required,  
  age: t.number,
  text: t.string.max(10).required,
}), 'validatorName');

or you can omit the validator name and assign the returning validator to a variable:

const myValidator = validator.create(t => ({
  user: t.string.required,  
  age: t.number,
  text: t.string.max(10).required,
}));

Finally, you can validate any json using the 'validate' function:

const json = {
  user: 'user',  
  age: 22,
  text: '123456789',
};
myValidator.validate(json);

You can also nest objects like this:

const demoValidator = validator.create(t => ({
  user: t.string.required,
  age: t.number,
  text: t.string.max(10).required,
  data: {
    token: t.string,
  },
}));

And you can check why a json is invalid:

const errors = demoValidator.errors();

Errors look like these:

[
  {
    message: 'element "key" must be string',
    type: 'string',
  },
  {
    message: 'key "user.name" should be upper than 10',
    type: 'string',
  },
  {
    message: 'key "user.age" should be positive',
    type: 'number',
  },
  {
    message: 'element "user.connection" must be date',
    type: 'date',
  },
]

Types

String

Validates if type is string. Example:

validator.create(t => ({
  key: t.string,
}));

You can use these validators in string type:

| Validator | Explaination | Example | | ------------- | ---------------------------- |:-----------------------------------------:| | required | makes key required | t.string.required | | shouldBe | checks if the values matches | t.string.shouldBe('apples', 'oranges') | | max(number) | maximum lenght limit | t.string.max(10) | | min(number) | minimum lenght limit | t.string.min(1) | | matches(regex)| tests if string matches regex| t.string.matches(/Regex/) |

Number

Validates if type is number. Example:

validator.create(t => ({
  key: t.number,
}));

You can use these validators in number type:

| Validator | Explaination | Example | | ------------- | ---------------------------- |:-------------------------:| | required | makes key required | t.number.required | | shouldBe | checks if the values matches | t.number.shouldBe(22, 21) | | positive | checks if number is positive | t.number.positive | | negative | checks if number is negative | t.number.negative |

Boolean

Validates if type is boolean. Example:

validator.create(t => ({
  key: t.boolean,
}));

You can use these validators in boolean type:

| Validator | Explaination | Example | | ------------- | ---------------------------- |:-------------------------:| | required | makes key required | t.boolean.required | | shouldBe | checks if the value matches | t.boolean.shouldBe(false) |

Array

Validates if type is array. Example:

validator.create(t => ({
  key: t.array,
}));

You can use these validators in array type:

| Validator | Explaination | Example | | --------------------- | -------------------------------------------------------- |:-------------------------------------:| | required | makes key required | t.array.required | | shouldBe | checks if the values matches | t.array.shouldBe([22, 21], [1, 'hi']) | | exactLength(number) | check if array length is exactly the specified length | t.array.exactLength(20) | | lengthLowerTo(number) | check if array length is lower to the specified length | t.array.lengthLowerTo(9) | | lengthUpperTo(number) | check if array length is upper to the specified length | t.array.lengthUpperTo(1) | | notEmpty | check if array legnth is not empty | t.array.notEmpty |

Date

Validates if type is date. Example:

validator.create(t => ({
  key: t.date,
}));

You can use these validators in date type:

| Validator | Explaination | Example | | ----------------- | ------------------------------------------ |:------------------------------------:| | required | makes key required | t.date.required | | shouldBe | checks if the values matches | t.date.shouldBe(new Date()) | | beforeDate(Date) | check if the date is before desired date | t.date.beforeDate(new Date()) | | afterDate(Date) | check if the date is after desired date | t.date.afterDate(new Date()) |

Express Framework Integration

You can use an express middleware to check jsons. You can do it calling to createMiddleware function to create a middleware:

const myValidator = validator.create(t => ({
  user: t.string.required,  
  age: t.number,
  text: t.string.max(10).required,
}));

app.post('/', validator.createMiddleware(myValidator), (req, res) => res.send(req.body););

The middleware, when a json is not valid, returns found errors. You can customize the returning status code:

const middleware = validator.createMiddleware(myValidator, 401);