ajv-pack

ajv-pack

Produces a compact module exporting JSON-schema validation functions compiled by Ajv

Purpose

This package allows to create standalone modules for validation functions that are pre-compiled and can be used without Ajv. It can be necessary for several reasons:

• to reduce the browser bundle size - Ajv is not included in the bundle (although if you have a large number of schemas the bundle can become bigger - when the total size of generated validation code is bigger than Ajv code).
• to reduce the startup time - the validation and compilation of schemas will happen during build time.
• to avoid dynamic code evaluation with Function constructor (used for schema compilation) - it can be prohibited in case Content Security Policy is used.

Please note: there are many cases when Ajv works as expected and ajv-pack does not. Some of these cases are listed in Limitations. It is recommended to test schemas compiled with this package more thoroughly than you would when using Ajv (which is very stable and well tested). Please submit issues with cases that fail.

Usage with CLI

In most cases you would use this package via ajv-cli (>= 1.0.0) to generate module that exports validation function.

npm install -g ajv-cli
ajv compile -s schema.json -o validate_schema.js

validate_schema.js will contain the module exporting validation function that can be bundled into your application.

Usage from code

npm install ajv-pack

var Ajv = require('ajv'); // version >= 4.7.4
var ajv = new Ajv({sourceCode: true}); // this option is required
var pack = require('ajv-pack');

var schema = {
  type: 'object',
  properties: {
    foo: {
      type: 'string',
      pattern: '^[a-z]+$'
    }
  }
};

var validate = ajv.compile(schema);
var moduleCode = pack(ajv, validate);

// now you can
// 1. write module code to file
var fs = require('fs');
var path = require('path');
fs.writeFileSync(path.join(__dirname, '/validate.js'), moduleCode);

// 2. require module from string
var requireFromString = require('require-from-string');
var packedValidate = requireFromString(moduleCode);

Ajv should still be a run-time dependency, but generated modules will only depend on some parts of it, the whole Ajv will not be included in the bundle if you require these modules from your code.

Limitations

At the moment ajv-pack does not support schemas with:

• custom 'compiled' and 'validated' keywords; custom inline and macro keywords are supported.
• custom formats (they will be ignored during validation).
• recursive references (reference to the current schema { "$ref": "#" } is supported).
• asynchronous schemas (they require custom keywords/formats).

License

MIT