Using npm:
$ npm i --save npm-nodejstesttask-pkg
//In Node.js e.g. index.js file of your project insert following code:
var nodejsModule = require('npm-nodejstesttask-pkg');
#Example
var array = [1,5,6,8,9];
nodejsModule.arrToString(array);
//Run index.js file with command:
node index.js