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);