check-verify

A module for validating function and method parameters with support for deep references using dot notation. Supports throwing errors and rejecting promises.

Basic Usage

check-verify exports two functions: thrower and promiser. Both return a CheckVerify object with slightly different behaviour.

thrower()

The thrower() function can be used in two ways: FailFast mode and Verify mode.

FailFast mode is enabled by providing an object to the thrower function. If no object is supplied to will default to Verify mode. Verify mode will wait for verify() to be called before validating whereas FailFast mode with execute the check as they are declared.

A thrower in Verify mode can be assigned to a variable and reused.

FailFast Mode

const thrower = require("check-verify").thrower;
 
function addUser(id, person) {
 
    thrower({ id, person })
        .check("id").is.a.number() // an error will be thrown here
        .check("person.first").is.a.string()
        .check("person.last").is.a.string()
        .optional("person.title").is.a.string();
 
        // do stuff
}
 
addUser("123", { first: "john", last: "doe"});

Verify Mode

const thrower = require("check-verify").thrower;
 
function addUser(id, person) {
 
    thrower()
        .check("id").is.a.number()
        .check("person.first").is.a.string()
        .check("person.last").is.a.string()
        .optional("person.title").is.a.string()
        .verify({ id, person }); // an error will be thrown here
 
        // do stuff
}
 
addUser("123", { first: "john", last: "doe"});

promiser()

The promiser method returns a CheckVerify object that will reject a promise instead of throwing an error. It does not support FailFast mode.

const promiser = require("check-verify").promiser;
 
function addUser(id, person) {
 
    return promiser()
        .check("id").is.a.number()
        .check("person.first").is.a.string()
        .check("person.last").is.a.string()
        .optional("person.title").is.a.string()
        
        .verify({ id, person })
        .then(() => {
            // do stuff
        })
        .catch(error => {
            // deal with error
        });
 
}
 
addUser("123", { first: "john", last: "doe"});

CheckVerify Syntax and methods

Supported validations

• boolean
• string
• number
• array
• object
• url
• date

Additional Grammar

• a
• an
• is
• that

For debugging purposes you can also use explain():

    const result = thrower()
        .check("id").is.a.number()
        .explain();
 
        console.log(result);
/*
 [ { field: 'id', tests: [ 'number' ] },
  { field: 'first', tests: [ 'string' ] } ]
*/

Road to v1

• review documentation
• improve keywords for npm search