Layer-one-validator NPM

layer-one-validator

Some expressjs middleware callback functions to validate data from requests, checks the amount of properties, their types and the business logic.

Installation and Usage

Server-side usage

Install the library with:

npm install layer-one-validator

The validator should be invoked using the bind() method. The first and only argument can be either an object or an array.

NOTE:: If the value being tested is an array, the type:function must be evaluated for each element within that array. In the case of the biz:function, testing can be performed on the entire array or on each individual element.

Syntax

layerOneValidator.body.bind(object)

layerOneValidator.body.bind(objectsArray)

Object

{ prop:string [, type:function][, biz:function][, optional:boolean] }

{ prop:string [, type:function][, biz:function][, optional:boolean] }[]

prop <string> - The name of the property named on the request.
type <function> - Optional, a function to test the type of the property. Should return a boolean.
biz <function> - Optional, a function to test the business part of the property. Should return a boolean.
optional <boolean> - Optional, default: false. When optional is set to true and the property exists on the incoming request, it must pass validation if a type or biz rule is defined.

Body, Query or Params

The layer-one-validator is an object with 3 properties, 'body','params' and 'query', representing each express request.

NOTE:: The Content-Type must be set to application/json when the data is sent in the body of the request.

Responses

If validation fails, the response will be a JSON object containing:

{ success: false } - Will throw an error on the server with additional information.
{ /* ... */, message } - Indicates the stage at which the failures occurred.
{ /* ... */, fail } - Displays the name of the failing property.
{ /* ... */, layer } - Displays 'body','params' or 'query'.
{ /* ... */, source } - Displays the source as layer-one-validator.

If successful, will go to the next middleware.

HTTP response status codes

If the bound object or objectsArray is incorrect, or if the type property function checks the entire array instead of individual items:

500 Internal Server Error

When issues are found with prop, type, or there are discrepancies in the number of properties:

400 Bad Request

When fails on biz:

422 Unprocessable Content

Route only

// route
const layerOneValidator = require('layer-one-validator');

router.post('/user',

    layerOneValidator.body.bind([
        { prop: 'weight', type: v => Number.isInteger(v), biz: v => v > 0 },
        { prop: 'username', biz: v => /^[a-z]{4,8}$/.test(v) }
    ]),

    (request, response, next) => {
        /* ... */
    }
);

module.exports = router;

Route & Helpers & Controller

// route
const userController = require(/* ... */);

router.post('/user',
    userController.user.validation.layerOne,
    userController.user.execute
);

// helpers - fns.js
module.exports = {
    isNumber: value => typeof value === 'number',
    isString: value => typeof value === 'string'
};

// helpers - biz.js
module.exports = {
    isWeight: value => Number.isInteger(value) && value > 0,
    isUsername: value => /^[a-z]{4,8}$/.test(value)
};

// controller
const layerOneValidator = require('layer-one-validator');
const fns = require('./path_to_helpers/fns');
const biz = require('./path_to_helpers/biz');

module.exports = {

    // * POST
    user: {

        validation: {
            layerOne: layerOneValidator.body.bind([
                { prop: 'weight', type: fns.isNumber, biz: biz.isWeight },
                { prop: 'username', type: fns.isString, biz: biz.isUsername }
            ])
        },

        execute(request, response, next) {
            /* ... */
        }
    }
};