NPM Module

Introduction

Luwak's built-in JavaScript engine supports full ES5 features and a small set of ES6 features. It is recommended to use Babeljs to convert ES6 code to ES5.

Before use, you can install it normally through npm install and test whether the library functions you need are normal. If there are no problems after testing, you don't need to convert to ES5.

Note: Luwak has a built-in JavaScript engine developed by Golang and does not support browser and Node.js container-specific APIs. Therefore only some NPM packages are supported. NPM packages that call Node.js-specific API cannot be used, for example: log4js-node

Third-party library

JavaScript has an extremely rich set of high-quality third-party libraries, such as:

Library	Github Star count	Purpose
axios	102K	HTTP client
lodash	57.7K	Basic function library, such as array/date operations
moment	47.6K	date operations
dayjs	44K	moment replacement
cheerio	27K	HTML parser
validator.js	21.9K	String validator
crypto-js	14.9K	Encryption and hash algorithm library
mathjs	13.6K	Mathematics
Numeral-js	9.5K	Number formatting

The richness of third-party libraries is one of the reasons why we chose JavaScript as the Luwak embedded scripting language.

Call NPM Module in Luwak

Consistent with normal node.js calls, for example:

var validator = require('validator.js');
var isEmail = validator.isEmail('foo@bar.com'); /* => true */

Install NPM Module

To use NPM Module in Luwak, you only need to "download source code-compile-copy". The following uses validator.js as an example to introduce the installation method in detail:

Download source code

Generally downloaded from github.com or npmjs.com:

• https://github.com/validatorjs/validator.js
• https://www.npmjs.com/package/validator.js

Compile

First, you need to modify the compilation output target to ES5, because Luwak's JavaScript engine only supports ES5.1 planning and does not fully support ES6:

jsconfig.json

{
   "compilerOptions": {
     "module": "system",
     "target": "ES5"
   }
}

Install dependencies and compile into node.js module:

yarn

yarn build:node

Copy

Copy the compiled product index.js file and lib directory to the _node_modules/validator.js/ directory of the Luwak installation directory

verify

Create a new RPC of com.example.test in Luwak and enter the following in the corresponding JS Code:

var validator = require('validator.js');

var isEmail = validator.isEmail('foo@bar.com'); /* => true */

var isNumeric = validator.isNumeric("1234567890"); /* => true */

var isNumeric = validator.isNumeric("N123456789"); /* => false */

Luwak’s preset NPM Module

• lodash -validator.js -crypto-js
• mathjs

These modules are in _node_modules in the luwak installation directory, and developers can freely upgrade or delete them.