I created an App that processes students results by extracting data from multiple excel workbooks. The problem is that using Puppeteer to generate the PDF files, throws the system into a loop till it hangs the system.
Actually, I have tested same codes below using PhantomJs which is bundled as pdf-creator-node, and was able to generate 150 PDF files comfortably in 3 minutes. The only challenge I dumped PhantomJs is that all the styling in the CSS file was not included, even when I inserted it as an inline style in the header, suing replace function of JS. Another, is that PhantomJs is no longer in active development. I searched the web, and found out that only Puppeteer is the valid solution with active development and support too.
I tried using page.close() at the end of pdfCreator() which is in a loop, and browser.close() at the end of pdfGenerator(). What I am doing wrong?
Here below are the codes in the server.js and PdfGenerator.js files, with a sample of the ERROR, and screenshot of my Task Manager after the system crawled out of hanging state. For HTML generation, I used Mustache. I excluded some lines of codes in server.js because the total character count was over 60k.
server.js
// [codes were removed here]
if(getCode == 'compute-result') {
// declare variable
let setData = null;
let setTitle = 'Results Computation...';
let setArgs = getArgs;
// dataFromFile = ReadFile(pathCodeTextFile);
// setArgs = Number(dataFromFile);
setCode = 'compute-result';
let setView = [];
let setNext = true;
let countTerms = [];
// if(getArg > 0) {
// Final Result computation
const getJson = ReadFile(pathJsonResults);
// const getCtrl = ReadFile(pathJsonCtrl);
const getResultObject = JSON.parse(getJson);
getResult = getResultObject;
const totalResults = getResult.firstTerm.length + getResult.secondTerm.length + getResult.thirdTerm.length;
if(setView.length < 1 && getResult != null) {
setData = 'PDFs for Students Results initiating...';
setView.unshift('Reading saved data...');
client.emit('query', {data: setData, title: setTitle, code: setCode, next: setNext, args: null, view: JSON.stringify(setView)});
}
Sleep(2000).then(() => {
if(getResult != null) {
setData = 'Students Results will be ready in a moment';
client.emit('query', {data: setData, title: setTitle, code: setCode, next: setNext, args: setArgs, view: JSON.stringify(setView)});
}
const wacthFiles = (file, className, termName, sessionName, completed, pdfList) => {
try {
if(typeof file == 'string' && !FileExists(pathJsonPdfList)) {
if(pdfList.length < 2){
setData = 'Saving PDFs to downladable files...';
}
if(className != null && termName != null && sessionName != null) {
setTitle = `${pdfList.length} Result PDF${pdfList.length > 1?'s':''}...`;
setView.unshift(file);
if(!countTerms.includes(termName)) {
countTerms.push(termName)
}
// setCode = -1000 - pdfList.length;
// console.log('PDF PROGRESS: ', `${pdfList.length} Result PDF${pdfList.length > 1?'s':''}... ${setCode}`);
// when all PDFs are created
if(completed) {
setTitle = setTitle.replace('...', ' [completed]');
setData = 'Result Download button is Active. You may click it now.';
setView.unshift('=== PDF GENERATION COMPLETED ===');
setView.unshift(`A total of ${pdfList.length} students' Results were generated`);
WriteFile(pathJsonPdfList, JSON.stringify(pdfList));
// set donwload button active
setCode = Number(codeTextFilePdfCompleted);
setNext = false;
getResult = null;
let termString = countTerms.toString();
termString = ReplaceAll(termString, '-term', '');
termString = ReplaceAll(termString, ',', '-');
const addTxt = `${className} _${termString} Term${countTerms.length>1?'s':''} (${sessionName})`;
WriteFile(pathCodeTextFile, addTxt);
// console.log('======== PDF GENERATION ENDS ================');
} else {
setCode = -1 * pdfList.length;
}
client.emit('query', {data: setData, title: setTitle, code: setCode, next: setNext, args: setArgs, view: JSON.stringify(setView)});
}
}
} catch (error) {
console.log('ERROR ON WATCHER: ', error);
}
}
if(!FileExists(pathJsonPdfList) && getResult !== null) {
PdfGenerator(getResult, wacthFiles);
}
// Watcher(pathWatchResults, setCode, wacthDir, 10000);
});
// }
}
}
} catch (error) {
})
client.on('disconnect', () => {
console.log('SERVER: Disconnected');
});
server.listen(portApi, () =>{
console.log('Server listens on port 8881')
});
// serve static files
app.use(express.static(pathPublic));
// [codes were removed here]
PdfGenerator.js
The problem lies in these functions: PdfGenerator & createPdf
'use strict';
process.setMaxListeners(Infinity) // fix for Puppeteer MaxListenerExceededWarning
const Puppeteer = require('puppeteer')
const {HtmlGenerator} = require('../components/HtmlGenerator')
const {WriteFile, FileExists, RandomNumber, RoundNumber, IsNumberFraction, ReadFile} = require('../components/Functions')
if (process.env.NODE_ENV !== 'production') {
require('dotenv').config();
}
const pathFirstTermResults = process.env.DIR_FIRST_TERM_RESULTS;
const pathSecondTermResults = process.env.DIR_SECOND_TERM_RESULTS;
const pathThirdTermResults = process.env.DIR_THIRD_TERM_RESULTS;
const publicDir = process.env.DIR_PUBLIC;
const cssFile = process.env.PATH_CSS_FILENAME;
const pathCssRaw = __dirname + '\\' + publicDir + '\\' + cssFile;
const pathCss = pathCssRaw.replace(`\\uploads`, '');
const tagCssReplace = process.env.TAG_CSS_REPLACE;
let jsonDir = process.env.PATH_JSON;
jsonDir = jsonDir.split('/').pop();
let htmlDir = process.env.DIR_HTML;
htmlDir = __dirname + '\\' + htmlDir.split('/').pop();
const htmlType1 = htmlDir + '\\' + process.env.HTML_TYPE1;
const htmlType2 = htmlDir + '\\' + process.env.HTML_TYPE2;
const htmlType3 = htmlDir + '\\' + process.env.HTML_TYPE3;
const pathJsonPdfList = './' + jsonDir + '/' + process.env.JSON_PDF_LIST_FILENAME;
const pathJsonPdfContent = __dirname + '\\' + jsonDir + '\\' + process.env.JSON_PDF_CONTENT;
const firstTermDir = 'first-term';
const secondTermDir = 'second-term';
const thirdTermDir = 'third-term';
let cumulativeFirstTermTotalList = {};
let cumulativeSecondTermTotalList = {};
let firstTermOnce = true;
let secondTermOnce = true;
let thirdTermOnce = true;
let isActive = false;
const getPath = (p, f) => {
let dir = pathFirstTermResults;
switch (p) {
case firstTermDir:
dir = pathFirstTermResults;
break;
case secondTermDir:
dir = pathSecondTermResults;
break;
case thirdTermDir:
dir = pathThirdTermResults;
break;
default:
break;
}
return dir + f
}
const resolution = {
x: 1920,
y: 1080
}
const args = [
'--disable-gpu',
`--window-size=${resolution.x},${resolution.y}`,
'--no-sandbox',
]
const createPdf = (page, content, templateType, filename, className, term, sessionName, isProcessActive, pdfFileList, cb) => {
let path, document, options;
path = getPath(term, filename);
if(path != null) {
let options = {
path: path,
format: 'A4',
printBackground: true,
margin: {
left: '0px',
top: '0px',
right: '0px',
bottom: '0px'
}
}
let templateData = '';
switch (templateType) {
case '1':
templateData = ReadFile(htmlType1);
break;
case '2':
templateData = ReadFile(htmlType2);
break;
case '3':
templateData = ReadFile(htmlType3);
break;
default:
templateData = ReadFile(htmlType1);
break;
}
(async() => {
const html = HtmlGenerator(content, templateData);
if(html != undefined && html !== '' && html != null) {
// create PDF file
cb(filename, className, term, sessionName, isProcessActive, pdfFileList);
// get style from .css & replace
const css = ReadFile(pathCss);
await page.setContent(html, { waitUntil: 'networkidle0'});
await page.addStyleTag(css);
await page.pdf(options);
page.close();
}
})()
}
}
const pdfGenerator = (json, cb) => {
let data = {};
let pdfFileList = [];
if(typeof json == 'string') {
data = JSON.parse(json)
} else {
data = json;
}
try {
// declare defaults
let filename = 'Student' + '.pdf';
let termName = firstTermDir;
const templateType = data.keys.templateType;
const session = data.classInfo.Session;
const sessionName = session.replace('/', '-');
const students = data.students;
const className = data.classInfo.Class_Name;
const recordFirstTerm = data.firstTerm;
const recordSecondTerm = data.secondTerm;
const recordThirdTerm = data.thirdTerm;
let pdfCreatedList = [];
let isReset = false;
let totalResultsExpected = Object.keys(recordFirstTerm).length + Object.keys(recordSecondTerm).length + Object.keys(recordThirdTerm).length;
let totalResultsCount = 0;
let jsonForPdf = {};
let record = {};
let sRecord, path, id, fName, lName;
// get each student
let logEndOnce = true;
let logBeforeOnce = true;
logBeforeOnce && console.log('============== *** ================');
logBeforeOnce && console.log('======== PDF GENERATION BEGINS ================');
const computeResult = (page, setTerm, setRecord, setReset) => {
const termName = setTerm;
const record = setRecord;
let isReset = setReset;
logBeforeOnce && console.log(`====== ${termName} RESULTS BEGINS ======`);
for(let elem of students){
id = elem.id;
fName = elem.firstName;
lName = elem.lastName;
filename = `${lName} ${fName} _${termName} ${sessionName}.pdf`;
// sRecord = record.filter(function (entry) { return entry[id] !== undefined; });
sRecord = record[id];
path = getPath(termName, filename);
// create pdf
if(!FileExists(path) && !FileExists(pathJsonPdfList)){
// generate final JSON for the student
// isReset = (pdfCreatedList.includes(id))? false: true;
jsonForPdf = finalJson(elem, sRecord, data, termName);
(pdfFileList.length < 1) && WriteFile(pathJsonPdfContent, JSON.stringify(jsonForPdf));
pdfFileList.push({
'term': termName,
'file': filename
});
totalResultsCount = pdfFileList.length;
const pdfDate = new Date();
console.log(`${filename} (${totalResultsCount}/${totalResultsExpected}) at ${pdfDate.getHours()}hr${pdfDate.getHours()>1?'s':''} - ${pdfDate.getMinutes()}min${pdfDate.getMinutes()>1?'s':''} - ${pdfDate.getSeconds()}sec${pdfDate.getSeconds()>1?'s':''}`);
isActive = (totalResultsExpected === totalResultsCount)? true: false;
logEndOnce = false;
// cb(filename, className, termName, sessionName, isActive, pdfFileList);
// WriteFile(path, null);
isReset = true;
createPdf(page, jsonForPdf, templateType, filename, className, termName, sessionName, isActive, pdfFileList, cb);
}
}
logBeforeOnce && console.log(`====== ${termName} RESULTS ENDS ======`);
}
// get each student result for First Term
const computeFirstTerm = (p) => {
return new Promise((resolve) => {
if(data.keys.firstTerm === '1') {
termName = firstTermDir;
record = recordFirstTerm;
pdfCreatedList = [];
isReset = false;
computeResult(p, termName, record, isReset)
}
resolve()
})
}
// get each student result for Second Term
const computeSecondTerm = (p) => {
return new Promise((resolve) => {
if(data.keys.secondTerm === '1') {
termName = secondTermDir;
record = recordSecondTerm;
pdfCreatedList = [];
isReset = false;
computeResult(p, termName, record, isReset)
}
resolve()
})
}
// get each student result for Third Term
const computeThirdTerm = (p) => {
return new Promise((resolve) => {
if(data.keys.thirdTerm === '1') {
termName = thirdTermDir;
record = recordThirdTerm;
pdfCreatedList = [];
isReset = false;
computeResult(p, termName, record, isReset)
}
resolve()
})
}
(async () => {
browser = await Puppeteer.launch({
headless: true,
handleSIGINT: false,
args: args,
});
const page = await browser.newPage();
await page.setViewport({
width: resolution.x,
height: resolution.y,
})
await computeFirstTerm(page);
await computeSecondTerm(page);
await computeThirdTerm(page);
browser.close()
})()
if(totalResultsExpected === totalResultsCount && totalResultsCount !== 0 && !logEndOnce) {
logEndOnce = true;
logBeforeOnce = false;
console.log('======== PDF GENERATION ENDS ================');
}
} catch (error) {
console.log('==== ERROR IN PDF GENERATION: ', error)
}
}
module.exports = {
PdfGenerator: pdfGenerator
}
ERROR
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
lerna ERR! yarn run start stderr:
<--- Last few GCs --->
[9884:000002D68A73C6B0] 1665171 ms: Scavenge 44.1 (45.8) -> 43.2 (45.8) MB, 223.9 / 0.0 ms (average mu = 0.956, current mu = 0.952) allocation failure
[9884:000002D68A73C6B0] 1684089 ms: Scavenge 44.1 (45.8) -> 43.3 (45.8) MB, 587.3 / 0.0 ms (average mu = 0.956, current mu = 0.952) allocation failure
[9884:000002D68A73C6B0] 1749901 ms: Scavenge 44.2 (45.8) -> 43.3 (45.8) MB, 5099.0 / 0.0 ms (average mu = 0.956, current mu = 0.952) allocation failure
<--- JS stacktrace --->
FATAL ERROR: Committing semi space failed. Allocation failed - JavaScript heap out of memory
1: 00007FF6ED61013F
2: 00007FF6ED59F396
3: 00007FF6ED5A024D
4: 00007FF6EDED19EE
5: 00007FF6EDEBBECD
6: 00007FF6EDD5F61C
7: 00007FF6EDD6933F
8: 00007FF6EDD5BF19
9: 00007FF6EDD5A0D0
10: 00007FF6EDD7EA06
11: 00007FF6EDAB1CD5
12: 00007FF6EDF5F3E1
13: 00007FF6EDF602E9
14: 000002D68C4EF69E
error Command failed with exit code 134.
Screenshot of Task Manager, Chromium running multiple instances of over 50.
I appreciate any help. I hope this can be resolved to give me a smooth PDF generation.
Thank you.
Example solution (limiting parallel browsers)
I created you a PdfPrinter class which you can integrate into your setup. It allows you to limit the amount of parallel pdf generation jobs and allows setting a limit and manages opening/closing the browser for you. The PdfPrinter class is also highly coupled and needed some modification for using it as a general queue. Logicwise this can be modified to be a general queue.
You can try to integrate that into your code. This is a fully working test example with simplified pdfs (without the part of getting the actual data from the excel..)
As far as I understood your code, you do not need to pass the page around all your functions. First create your html + css and then use the pdfPrinter and let it handle page creation + browser launching..
(I like to code stuff like this so I went straight ahead..)
var puppeteer = require('puppeteer')
const defaultPrinterOptions = {
format: 'A4',
printBackground: true,
margin: {
left: '0px',
top: '0px',
right: '0px',
bottom: '0px'
}
}
class PdfPrinter {
maxBrowsers = 2
enqueuedPrintJobs = []
failedJobs = []
browserInstances = 0
// max browser instances in parallel
constructor(maxBrowsers) {
this.maxBrowsers = maxBrowsers
}
/**
*
* #param {*} html the html content to print
* #param {*} css to apply to the page
* #param {*} printOptions options passed to puppeteer
*/
// enqueues a print but the exact end moment cannot be known..
enqueuePrint = (html, css, path, done) => {
// merge custom options with defaultOptions..
const printOptions = {
...defaultPrinterOptions,
// add the path to the options.
path: path
}
// create a function which can be stored in an array
// it will later be grabbed by startPrinter() OR at the time any
// brwoser freed up..
// the function needs to be passed the actual used browser instance!
this.enqueuedPrintJobs.push(async(browser) => {
// catch the error which may be produced when printing something..
try {
// print the document
await this.print(browser, html, css, printOptions)
} catch (err) {
console.error('error when printing document..CLosing browser and starting a new job!!', printOptions.path)
console.error(err)
// store someting so you now what failed and coudl be retried or something..
this.failedJobs.push({ html, css, path: printOptions.path })
// puppeteer can run into erros too!!
// so close the browser and launch a new one!
await this.closeBrowser(browser)
browser = await this.launchBrowser()
}
// after the print, call done() so the promise is resovled in the right moment when
// this particular print has ended.!
done()
// start the next job right now if there are any left.
const job = this.enqueuedPrintJobs.shift()
if (!job) {
console.log('No print jobs available anymore. CLosing this browser instance.. Remaining browsers now:', this.maxBrowsers - this.browserInstances + 1)
await this.closeBrowser(browser)
return
}
// job is actually this function itself! It will be executed
// and automatically grab a new job after completion :)
// we pass the same browser instance to the next job!.
await job(browser)
})
// whenever a print job added make sure to start the printer
// this starts new browser instances if the limit is not exceeded resp. if no browser is instantiated yet,
// and does nothing if maximum browser count is reached..
this.tryStartPrinter()
}
// same as enqueuePrint except it wraps it in a promise so we can now the
// exact end moment and await it..
enqueuePrintPromise(html, css, path) {
return new Promise((resolve, reject) => {
try {
this.enqueuePrint(html, css, path, resolve)
} catch (err) {
console.error('unexpected error when setting up print job..', err)
reject(err)
}
})
}
// If browser instance limit is not reached will isntantiate a new one and run a print job with it.
// a print job will automatically grab a next job with the created browser if there are any left.
tryStartPrinter = async() => {
// Max browser count in use OR no jobs left.
if (this.browserInstances >= this.maxBrowsers || this.enqueuedPrintJobs.length === 0) {
return
}
// browser instances available!
// create a new one
console.log('launching new browser. Available after launch:', this.maxBrowsers - this.browserInstances - 1)
const browser = await this.launchBrowser()
// run job
const job = this.enqueuedPrintJobs.shift()
await job(browser)
}
closeBrowser = async(browser) => {
// decrement browsers in use!
// important to call before closing browser!!
this.browserInstances--
await browser.close()
}
launchBrowser = async() => {
// increment browsers in use!
// important to increase before actualy launching (async stuff..)
this.browserInstances++
// this code you have to adjust according your enviromnemt..
const browser = await puppeteer.launch({ headless: true })
return browser
}
// The actual print function which creates a pdf.
print = async(browser, html, css, printOptions) => {
console.log('Converting page to pdf. path:', printOptions.path)
// Run pdf creation in seperate page.
const page = await browser.newPage()
await page.setContent(html, { waitUntil: 'networkidle0' });
await page.addStyleTag({ content: css });
await page.pdf(printOptions);
await page.close();
}
}
// testing the PDFPrinter with some jobs.
// make sure to run the printer in an `async` function so u can
// use await...
const testPrinterQueue = async() => {
// config
const maxOpenedBrowsers = 5 // amount of browser instances which are allowed to be opened in parallel
const testJobCount = 100 // amount of test pdf jobs to be created
const destDir = 'C:\\somepath' // the directory to store the pdfs in..
// create sample jobs for testing...
const jobs = []
for (let i = 0; i < testJobCount; i++) {
jobs.push({
html: `<h1>job number [${i}]</h1>`,
css: 'h1 { background-color: red; }',
path: require('path').join(destDir, `pdf_${i}.pdf`)
})
}
// track time
const label = 'printed a total of ' + testJobCount + ' pdfs!'
console.time(label)
// run the actual pdf generation..
const printer = new PdfPrinter(maxOpenedBrowsers)
const jobProms = []
for (let job of jobs) {
// run jobs in parallel. Each job wil be runned async and return a Promise therefor
jobProms.push(
printer.enqueuePrintPromise(job.html, job.css, job.path)
)
}
console.log('All jobs enqueued!! Wating for finish now.')
// helper function which awaits all the print jobs, resp. an array of promises.
await Promise.all(jobProms)
console.timeEnd(label)
// failed jobs::
console.log('jobs failed:', printer.failedJobs)
// as file:
await require('fs').promises.writeFile('failed-jobs.json', JSON.stringify(printer.failedJobs))
}
testPrinterQueue().then(() => {
console.log('done with everyting..')
}).catch(err => {
console.error('unexpected error occured while printing all pages...', err)
})
You only need to adjust the destDir / openedBrowsers and testJobCount vars in the beginning of testPrinterQueue() for getting this to work.
What caused the problem in your code
Let's have a look at this piece
(async () => {
browser = await Puppeteer.launch({
headless: true,
handleSIGINT: false,
args: args,
});
const page = await browser.newPage();
await page.setViewport({
width: resolution.x,
height: resolution.y,
})
await computeFirstTerm(page);
await computeSecondTerm(page);
await computeThirdTerm(page);
browser.close()
})()
You created an anonymous function which is executed immediatly. Within the function all the statements are correctly awaited using await. But if you run this whole piece within a synchronious part of your application, the whole function will start immediatly but NOT been awaited before running next code.
Checkout this example:
//utility
function wait(ms) {
return new Promise(resolve => {
setTimeout(resolve, ms)
})
}
const AsyncFunction = async() => {
console.log('Async named function started')
// simulate execution time of 2 seconds
await wait(2000)
console.log('Async named function ended')
};
function SyncFunction() {
console.log('sync function started')
// example of async function execution within a sync function..
AsyncFunction();
// what you have done in your code:
(async() => {
console.log('Async anonymus function started')
await wait(3000)
console.log('Async anonymus function ended')
})()
// what
console.log('sync function ended.')
}
SyncFunction()
console.log('done')
Note the output:
Async named function started
Async anonymus function started
sync function ended. // => sync function already ended
done // sync function ended and code continues execution.
Async named function ended
Async anonymus function ended
To correctly await your async stuff you need to put your whole application in async scope:
//utility
function wait(ms) {
return new Promise(resolve => {
setTimeout(resolve, ms)
})
}
const AsyncFunction = async() => {
console.log('Async named function started')
// simulate execution time of 2 seconds
await wait(2000)
console.log('Async named function ended')
};
// this is now async!!
async function SyncFunction() {
console.log('sync function started')
// example of async function execution within a sync function..
await AsyncFunction();
// what you have done in your code:
await (async() => {
console.log('Async anonymus function started')
await wait(3000)
console.log('Async anonymus function ended')
})()
// what
console.log('sync function ended.')
}
SyncFunction().then(() => {
console.log('done')
}).catch(err => {
console.error('unexpected error occured..')
})
This output is what we want
sync function started
Async named function started
Async named function ended
Async anonymus function started
Async anonymus function ended
sync function ended.
done
Hope this helps you understand.
Feel free to leave a comment.
Jest has this feature to log the line that outputs to console methods.
In some cases, this can become annoying:
console.log _modules/log.js:37
ℹ login.0 screenshot start
console.time _modules/init.js:409
login.0.screenshot: 0.33ms
console.time _modules/init.js:394
0 | login.0: 0.524ms
console.log _modules/log.js:37
ℹ login.1 screenshot start
Any idea how I can turn it off?
With Jest 24.3.0 or higher, you can do this in pure TypeScript by adding the following to a Jest setup file configured in setupFilesAfterEnv:
import { CustomConsole, LogType, LogMessage } from '#jest/console';
function simpleFormatter(type: LogType, message: LogMessage): string {
const TITLE_INDENT = ' ';
const CONSOLE_INDENT = TITLE_INDENT + ' ';
return message
.split(/\n/)
.map(line => CONSOLE_INDENT + line)
.join('\n');
}
global.console = new CustomConsole(process.stdout, process.stderr, simpleFormatter);
Jest injects custom console implementation that is based on extendable Console class into test global scope. Normally it provides useful debugging information alongside printed message that answers the question where potentially unwanted output comes from.
In case this is undesirable for some reason, a simple way to retrieve default console implementation is to import it from Node built-in module.
Can be done for specific console calls:
let console = require('console');
...
console.log(...)
For many of them that occur inside a range of tests:
const jestConsole = console;
beforeEach(() => {
global.console = require('console');
});
afterEach(() => {
global.console = jestConsole;
});
And so on.
Update: For newer versions of Jest, see Harald Wellmann's answer.
Looking at the source code for Jest, it doesn't seem like there is a neat way to turn those messages off.
However, one possible solution could be to write your own Console. Here I have used Console.js from Jest as a starting ground, and then created SimpleConsole which does what you need (I have removed some terminal coloring features for simplicity, but you could just add them yourself).
Once added to your project, you can overwrite Jest's normal console with your own before running the tests:
const { SimpleConsole } = require('./SimpleConsole');
global.console = new SimpleConsole(process.stdout, process.stderr);
I have made a REPL that shows it in action.
The source code for SimpleConsole:
const path = require('path');
const assert = require('assert');
const {format} = require('util');
const {Console} = require('console');
function simpleFormatter() {
const TITLE_INDENT = ' ';
const CONSOLE_INDENT = TITLE_INDENT + ' ';
return (type, message) => {
message = message
.split(/\n/)
.map(line => CONSOLE_INDENT + line)
.join('\n');
return (
message +
'\n'
);
};
};
class SimpleConsole extends Console {
constructor(stdout, stderr, formatBuffer) {
super(stdout, stderr);
this._formatBuffer = formatBuffer || simpleFormatter();
this._counters = {};
this._timers = {};
this._groupDepth = 0;
}
_logToParentConsole(message) {
super.log(message);
}
_log(type, message) {
if (process.stdout.isTTY) {
this._stdout.write('\x1b[999D\x1b[K');
}
this._logToParentConsole(
this._formatBuffer(type, ' '.repeat(this._groupDepth) + message),
);
}
assert(...args) {
try {
assert(...args);
} catch (error) {
this._log('assert', error.toString());
}
}
count(label = 'default') {
if (!this._counters[label]) {
this._counters[label] = 0;
}
this._log('count', format(`${label}: ${++this._counters[label]}`));
}
countReset(label = 'default') {
this._counters[label] = 0;
}
debug(...args) {
this._log('debug', format(...args));
}
dir(...args) {
this._log('dir', format(...args));
}
dirxml(...args) {
this._log('dirxml', format(...args));
}
error(...args) {
this._log('error', format(...args));
}
group(...args) {
this._groupDepth++;
if (args.length > 0) {
this._log('group', chalk.bold(format(...args)));
}
}
groupCollapsed(...args) {
this._groupDepth++;
if (args.length > 0) {
this._log('groupCollapsed', chalk.bold(format(...args)));
}
}
groupEnd() {
if (this._groupDepth > 0) {
this._groupDepth--;
}
}
info(...args) {
this._log('info', format(...args));
}
log(...args) {
this._log('log', format(...args));
}
time(label = 'default') {
if (this._timers[label]) {
return;
}
this._timers[label] = new Date();
}
timeEnd(label = 'default') {
const startTime = this._timers[label];
if (startTime) {
const endTime = new Date();
const time = endTime - startTime;
this._log('time', format(`${label}: ${time}ms`));
delete this._timers[label];
}
}
warn(...args) {
this._log('warn', format(...args));
}
getBuffer() {
return null;
}
}
module.exports.SimpleConsole = SimpleConsole;
If you want to use Haral Wellmann's answer but avoid typescript, then you can merely do something like:
const JestConsole = require('./node_modules/#jest/console');
global.console = new JestConsole.CustomConsole(process.stdout, process.stderr, (type, message) => {
const TITLE_INDENT = ' ';
const CONSOLE_INDENT = TITLE_INDENT + ' ';
return message.split(/\n/).map(line => CONSOLE_INDENT + line).join('\n');
});
None of the above options worked for me.
The (current) simplest solution is this:
1: Create a file with this code (e.g. config.js)
import console from "console"
global.console = console
2: Add this line to your jest.config.js
setupFilesAfterEnv: ["./config.js"]
Before:
After:
Enjoi!
Lets say I have a file file1.js which contains:
const a = true;
let b;
if (a) {
b = c;
}
if (!a) {
b = d;
}
Now when I run test case on this file my first condition gets covered. Is there any way that I can cover second condition by setting a to false or should I change my code in a way that I can call a method with different values to test for each case kind of like:
const a = true;
getBVal(a) {
return a ? c : d;
}
let b = getBVal(a);
Update:
Below is my code for requestAnimationFrame with fallbacks for older browsers:
let lastTime = 0;
const vendors = ["ms", "moz", "webkit", "o"];
let rAF = window.requestAnimationFrame;
if (!rAF) {
rAF = vendors.find(prefix => window[`${prefix}RequestAnimationFrame`]);
}
if (!rAF) {
rAF = cB => {
const currTime = new Date().getTime();
const timeToCall = Math.max(0, 16 - (currTime - lastTime));
const id = setTimeout(() => {
cB(currTime + timeToCall);
}, timeToCall);
lastTime = currTime + timeToCall;
return id;
};
}
function requestAnimationFrame(callback) {
return rAF(callback);
}
export default requestAnimationFrame;
I am using jsdom in setup for window object. Now if I have to test case for window.requestAnimationFrame = null its not possible in the way I have written my code
Now after changing it to:
import { requestAnimationFrameVendor } from "../constants";
let lastTime = 0;
const customFn = cB => {
const currTime = new Date().getTime();
const timeToCall = Math.max(0, 16 - (currTime - lastTime));
const id = setTimeout(() => {
cB(currTime + timeToCall);
}, timeToCall);
lastTime = currTime + timeToCall;
return id;
};
function requestAnimationFrame(callback) {
const rAF = window.requestAnimationFrame;
return rAF && rAF(callback) || requestAnimationFrameVendor && requestAnimationFrameVendor(callback) || customFn(callback);
}
export default requestAnimationFrame;
And then if I write test like:
import * as constants from "../../constants";
describe("animationFrame", () => {
let requestAnimationFrame;
let cancelAnimationFrame;
beforeAll(() => {
requestAnimationFrame = global.window.requestAnimationFrame;
cancelAnimationFrame = global.window.cancelAnimationFrame;
});
test("requestAnimationFrame", done => {
global.window.requestAnimationFrame = null;
global.window.cancelAnimationFrame = null;
const requestId1 = Utils.requestAnimationFrame(jest.fn());
constants.requestAnimationFrameVendor = jest.fn(() => {
return requestAnimationFrame;
});
const requestId2 = Utils.requestAnimationFrame(jest.fn());
setTimeout(() => {
Utils.cancelAnimationFrame(requestId1);
Utils.cancelAnimationFrame(requestId2);
done();
}, 300);
});
afterEach(() => {
global.window.webkitRequestAnimationFrame = null;
global.window.webkitCancelAnimationFrame = null;
});
});
Then it covers all the conditions.
I would go the second rout (getBVal()) because it makes your interface more testable.
In general, removing global state (like your const a or let b) will make your code and interfaces more testable. If you cannot remove the global state completely, you can introduce abstractions so that your test does not need to know about the global state (like your suggested getBVal()).
Maybe you can go even further and remove the global b: Instead always call getBVal() instead? The performance impact will be negligible in most cases, and your code becomes even more testable and less coupled...
I'm trying to get sinon.stub to work for async function. I have created promiseFunction.js:
let functionToBeStubbed = async function() {
return ("Text to be replaced by stub.");
};
let promiseFunction = async function() {
return(await functionToBeStubbed());
};
module.exports = {
promiseFunction: promiseFunction,
functionToBeStubbed: functionToBeStubbed
};
and test promiseFunction.spec.js:
let functionstobestested = require('./promiseFunction.js');
describe('Sinon Stub Test', function () {
var sandbox;
it('should return --Text to be replaced by stub.--', async function () {
let responsevalue = "The replaced text.";
sandbox = sinon.sandbox.create();
sandbox.stub(functionstobestested, 'functionToBeStubbed').resolves(responsevalue);
//sandbox.stub(functionstobestested, 'functionToBeStubbed').returns(responsevalue);
let result = "Empty";
console.log(`BEFORE: originaldata = ${result}, value = ${responsevalue}`);
result = await functionstobestested.promiseFunction();
console.log(`AFTER: originaldata = ${result}, value = ${responsevalue}`);
expect(result).to.equal(responsevalue);
sandbox.restore();
console.log("AFTER2: Return value after restoring stub: " + await functionstobestested.promiseFunction());
});
});
when running the test, I will get
test failure
If I modify export slightly, it still fails:
var functionsForTesting = {
promiseFunction: promiseFunction,
functionToBeStubbed: functionToBeStubbed
};
module.exports = functionsForTesting;
I do not understand why this test fails, as it should pass. If I change the way I export functions from promiseFunction.js - module, the test pass correctly. Revised promiseFunction.js:
const functionsForTesting = {
functionToBeStubbed: async function() {
return ("Text to be replaced by stub.");
},
promiseFunction: async function() {
return(await functionsForTesting.functionToBeStubbed());
};
module.exports = functionsForTesting;
Test pass
What's wrong in my original and modified way to export functions?