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 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
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 'validate' function:
const json = {
user: 'user',
age: 22,
text: '123456789',
};
validator.validate(json, 'validatorName');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 looks like this:
[
{
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 this validators in string type:
| Validator | Explanation | Example |
|---|---|---|
| required | makes key required | t.string.required |
| shouldBe | checks if the values matches | t.string.shouldBe('apples', 'oranges') |
| max(number) | maximum limit | t.string.max(10) |
| min(number) | minimum 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 this validators in number type:
| Validator | Explanation | 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 this validators in boolean type:
| Validator | Explanation | 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 this validators in array type:
| Validator | Explanation | 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 this validators in date type:
| Validator | Explanation | 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 our middleware with express to check jsons. You can do it calling to createMiddleware function to create a middleware:
validator.create(t => ({
user: t.string.required,
age: t.number,
text: t.string.max(10).required,
}), 'name');
app.post('/', validator.createMiddleware('name'), (req, res) => res.send(req.body););By default, the middleware, when a json is not valid, returns this json with html status code 400:
{ status: 400, message: 'invalid json' }
You can customize this passing to createMiddleware your json and the status code:
const json = {
error: 'bad json',
};
const middleware = validator.createMiddleware('validator name', json, 401);
