changed: manage browser instances to improve performance of tests and…

… using this library as a JS module

.eslintrc.json

@@ -41,7 +41,6 @@
         "jsdoc/check-param-names": 1,
         "jsdoc/check-tag-names": 1,
         "jsdoc/check-types": 1,
-        "jsdoc/newline-after-description": ["warn", "always"],
         "jsdoc/no-undefined-types": 1,
         "jsdoc/require-description": 0,
         "jsdoc/require-description-complete-sentence": 0,

CHANGELOG.md

@@ -8,6 +8,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ##### Changed
 - Updated dependencies.
+- Improved performance of tests and using this library as a JS module
 
 [2.1.2] - 2023-03-01
 --------------------------

package.json

@@ -5,7 +5,7 @@
     "main": "src/validator.js",
     "bin": "./validate",
     "scripts": {
-        "test": "mocha test/spec/*.spec.js --exit --timeout 9000 && npm run style-check",
+        "test": "mocha test/spec/*.spec.js --exit --timeout 6000 && npm run style-check",
         "build-docs": "rimraf docs && ./node_modules/.bin/jsdoc -c jsdoc.config.js",
         "prepare": "rollup --config && rollup --config rollup.utils.config.mjs",
         "style-fix": "eslint *.js src/**/*.js test/**/*.js --fix",

src/headless-browser.js

@@ -0,0 +1,43 @@
+const puppeteer = require( 'puppeteer' );
+
+/**
+ * This class approach makes it easy to open multiple browser instances with
+ * different arguments in case that is ever required.
+ */
+class BrowserHandler {
+    constructor() {
+        const launchBrowser = async() => {
+            this.browser = false;
+            this.browser = await puppeteer.launch( {
+                headless: 'new',
+                devtools: false
+            } );
+            this.browser.on( 'disconnected', launchBrowser );
+        };
+
+        this.exit = ()=>{
+            this.browser.off( 'disconnected', launchBrowser );
+            this.browser.close();
+        };
+
+        ( async() => {
+            await launchBrowser();
+        } )();
+    }
+}
+
+const getBrowser = ( handler ) =>
+    new Promise( ( resolve ) => {
+        const browserCheck = setInterval( () => {
+            if ( handler.browser !== false ) {
+                clearInterval( browserCheck );
+                resolve( handler.browser );
+            }
+        }, 100 );
+    } );
+
+const closeBrowser = ( handler ) => {
+    return handler.exit();
+};
+
+module.exports = { BrowserHandler, getBrowser, closeBrowser };

src/validator.js

@@ -5,6 +5,7 @@
 'use strict';
 
 const { XForm } = require( './xform' );
+const { BrowserHandler } = require( './headless-browser' );
 /**
  * @constant
  * @static
@@ -30,18 +31,19 @@ const { version } = require( '../package' );
  *
  * @static
  * @param {string} xformStr - XForm content.
+ * @param browserHandler
  * @param {ValidationOptions} [options] - Validation options.
  * @return {ValidateResult} validation results.
  */
-const validate = async( xformStr, options = {} ) => {
+const validate = async( xformStr, browserHandler = new BrowserHandler(), options = {} ) => {
     const start = Date.now();
     let warnings = [];
     let errors = [];
     let result = {};
     let xform;
 
     try {
-        xform = new XForm( xformStr, options );
+        xform = new XForm( xformStr, browserHandler, options );
     } catch ( e ) {
         errors.push( e );
     }

src/xform.js

@@ -1,14 +1,15 @@
 global.IntersectionObserver = function(){};
 const utils = require( '../build/utils-cjs-bundle' );
 const { JSDOM } = require( 'jsdom' );
-const puppeteer = require( 'puppeteer' );
+const { BrowserHandler, getBrowser } = require( './headless-browser' );
 const libxslt = require( 'libxslt' );
 const libxmljs = libxslt.libxmljs;
 const path = require( 'path' );
 const sheets = require( 'enketo-transformer' ).sheets;
 const xslModelSheet = libxslt.parse( sheets.xslModel );
 const appearanceRules = require( './appearances' );
 
+
 /**
  * @typedef Result
  * @property {Array<string>} warnings - List of warnings.
@@ -24,9 +25,10 @@ class XForm {
      * @constructs
      *
      * @param {string} xformStr - XForm content.
+     * @param browserHandler
      * @param {module:validator~ValidateResult} [options] - Validation options.
      */
-    constructor( xformStr, options = {} ) {
+    constructor( xformStr, browserHandler = new BrowserHandler(), options = {} ) {
         this.options = options;
         if ( !xformStr || !xformStr.trim() ) {
             throw 'Empty form.';
@@ -35,8 +37,9 @@ class XForm {
 
         const dom = this._getDom();
         this.doc = dom.window.document;
-        this.loadBrowserPage = puppeteer.launch( { headless: 'new', devtools: false } )
-            .then( browser => {
+
+        this.loadBrowserPage = getBrowser( browserHandler )
+            .then( browser =>{
                 this.browser = browser;
 
                 return browser.newPage();
@@ -167,10 +170,8 @@ class XForm {
     }
 
     exit(){
-        if ( this.browser ){
-
-            return this.browser.close();
-        }
+        return this.loadBrowserPage
+            .then( page => page.close() );
     }
 
     /**