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:

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

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

`javascript
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:

`javascript
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:

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

You can also nest objects like this:

`javascript
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:

`javascript
const errors = demoValidator.errors();
`

Errors look like these:

`javascript
[
{
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

$3

Validates if type is string. Example:

`javascript
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/) |

$3

Validates if type is number. Example:

`javascript
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 |

$3

Validates if type is boolean. Example:

`javascript
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) |

$3

Validates if type is array. Example:

`javascript
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 |

$3

Validates if type is date. Example:

`javascript
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:

`javascript
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:

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