when I type start node into the cmd it starts up a new node terminal like this:
but how do I get it to run a script in the node terminal and close it after it's done?
maybe something like this?
start node "index.js" (when I try this it opens a terminal then immediately closes)
index.js:
console.log('hello there!');
await new Promise(r=>setTimeout(r,3000));
Top-level awaits aren't supported in Node versions prior to 14.18.0; there is a helpful discussion on GitHub as to why.
Since you're running v14.17.6, you'll need to wrap your code in an anonymous async function, then invoke it with ():
(async () => {
console.log('hello there!');
await new Promise(r=>setTimeout(r,3000));
})();
The resulting Node terminal will await for your timeout period before being closed.
(It may also behoove those reading this answer to ensure that they are correctly referencing the script they wish to execute relative to their command line's current working directory; see comment below by #cakelover.)
Related
I am working on a Docker Swarm data visualization tool with a team.
It works as follows:
Our backend is set up in a way that terminal commands can be executed from our code, where these terminal commands have been promisified and the result of this command should be a string of nodeIDs corresponding to the active nodes in my Docker Swarm. This data is then passed to another helper function, however, I am unable to move past the previously explained step due to an unexpected output from my promisified terminal command.
const getNodeIDs = () => {
console.log('in nodeID helper function');
return execProm("docker node ls --format '{{json .ID}}'").then(
(rawNodeIDs) => {
console.log('rawNodeIds: ', rawNodeIDs);
const parsedNodeIDs = parseRawData(rawNodeIDs);
console.log('parsedNodeIDs: ', parsedNodeIDs);
return parsedNodeIDs;
}
);
};
My code fails on line 6 due to the fact that the data being passed to my parseRawData function is not what it is expected. The console log on line 5 above returns as follows:
{
stdout: 'Saved file tree to doc-filelist.js\n' +
'Copied JS to doc-script.js\n' +
'Compiled CSS to doc-style.css\n',
stderr: ''
}
In addition to this being the wrong output, every time I invoke this command, a new file is created in my codebase labeled "docs" with the following three files inside: doc-filelist.js, doc-script.js, doc-style.css. I am working in a team of 4 other engineers, and I seem to be the only person experiencing this behavior. When I attempt to run the terminal command (featured on line 3 in the first block of code) directly in the terminal itself, I receive the expected output of
"odwch32vsynhxbc0ia2nwicag"
which is the nodeID of the single node currently in my Docker Swarm and what I should be receiving when invoking the terminal command from the code.
I've only been able to find one other stack overflow article dealing with the same issue in which that person was told to try running the terminal command
npm uninstall -g docker
which I have done, and this did not fix my issues. I've also looked into making edits to the Docker daemon itself, but am unsure that this is the real root of the issue. Since I am the only person on my team that seems to be encountering this bug, I have reason to believe that this error has something to do with my dev environment. My containers are running on Docker v4.15.0 and I am working on macOS on an M1 chip computer.
Thanks!
i am writting tests for a node application which uses bull to process background jobs.
the test seems to be passing and working as expected but i am seeing the following error message
Jest has detected the following
8 open handles potentially keeping
Jest from exiting:
the log points to specifically this line and other similar statements.
const csvExportsQueue = ['test', 'development'].includes(process.env.NODE_ENV) ? new Queue('exports') : new Queue('csv exports', 'redis://redis:6379/13');
I tried to add the below statement to my test but it still gives the same error
afterAll(async () => {
await new Promise(resolve => setTimeout(() => resolve(), 10000)); // avoid jest open handle error
});
any help on how to fix this will be great, thanks.
add "jest --detectOpenHandles" to "test" in package.json to see the openhandles for Debugging
check your db connection (most likely) and close it them with connection.end()
I am using rotateByDegrees from a library called node-poweredup in a typescript project:
motor.rotateByDegrees(20,10).then(function(value) {console.log("test");}, function(value) {console.log("error");});
I would expect to see "test" after successful completion, but the promise never resolves. If I use await, it hangs on the await line forever.
Replicating the syntax that appears to be used in the rotateByDegrees function:
let promise = new Promise((resolve) => { return resolve(); });
does not compile, I get error TS2794: Expected 1 arguments, but got 0. Did you forget to include 'void' in your type argument to 'Promise'? I can make it compile and behave as expected with resolve(true), but how does it compile in the library then? Do I misunderstand promises? Some feature in typescript? A bug in the library? I am a newbie to JavaScript, I don't want to over-complicate this question by including irrelevant details. If you can give me hints on what I am missing and how to debug this, I can provide all relevant details.
Thanks to the helpful comments I was able to narrow it down to the compilation of the library. I did in fact not use a pre-compiled binary but had to compile the library myself using electron-rebuild to make the bluetooth adapter work. I did the following test:
git clone https://github.com/nathankellenicki/node-poweredup.git
cd node-poweredup
npm install
npm run build
this compiles without error. I created the following test file
const PoweredUP = require("node-poweredup");
const poweredUP = new PoweredUP.PoweredUP();
poweredUP.scan(); // Start scanning for hubs
console.log("Looking for Hubs...");
poweredUP.on("discover", async (hub) => { // Wait to discover hubs
await hub.connect(); // Connect to hub
console.log(`Connected to ${hub.name}!`);
const motorA = await hub.waitForDeviceAtPort("A"); // Make sure a motor is plugged into port A
motorA.rotateByDegrees(20,10).then(function(value) {console.log("test");});
});
and get the expected output:
node-poweredup$ node test.js
Looking for Hubs...
Connected to MyHub2!
test
Connected to MyHub3!
test
When I changed the first line to
const PoweredUP = require(".");
to make it use my self-compiled binary I get
node-poweredup$ node test.js
Looking for Hubs...
Connected to MyHub2!
Connected to MyHub3!
Of course this is only a partial answer because I still don't know why it compiles differently on my machine, but at least I have an idea where to start searching for the problem.
I have a module that exports a method used in JEST test. I want to run it from command line too.
async function doRun() { /* do something */}
exports.doRun = doRun;
This works well from JEST, where I import the module and execute the method. But when I call it with node module.js, it has no effect because the method is not executed within JS body. To fix it I have to add:
doRun().then(() => console.log('finished'));
which makes the code work from CLI but it is executed too in JEST just after import.
Am I right that I need to create new file that imports the module and runs the code just for CLI?
const module = require('module.js')
doRun().then(() => console.log('finished'));
and then run node module_cli.js?
Pretty much, yeah. :-)
Either that, or use an environment variable
async function doRun() { /* do something */}
exports.doRun = doRun;
if (process.env.AUTO_RUN === "Y") {
doRun().then(() => console.log('finished'));
}
and run it like this on *nix:
AUTO_RUN=Y node module.js
...or on Windows according to this it would be:
cmd /V /C "set AUTO_RUN=Y&&node module.js"
You could also use the standard NODE_ENV environment variable. I haven't gotten deep into Jest, but it might set it to "testing" or something like that...
I'm trying to get webdriver.io and Jasmine working.
Following their example, my script is at test/specs/first/test2.js (in accordance with the configuration) and contains:
var webdriverio = require('webdriverio');
describe('my webdriverio tests', function() {
var client = {};
jasmine.DEFAULT_TIMEOUT_INTERVAL = 9999999;
beforeEach(function() {
client = webdriverio.remote({ desiredCapabilities: {browserName: 'firefox'} });
client.init();
});
it('test it', function(done) {
client
.url("http://localhost:3000/")
.waitForVisible("h2.btn.btn-primary")
.click("h2.btn.btn-primary")
.waitForVisible("h2.btn.btn-primary")
.call(done);
});
afterEach(function(done) {
client.end(done);
});
});
I'm using wdio as the test runner, and set it up using the interactive setup. That config is automatically-generated and all pretty straightforward, so I don't see a need to post it.
In another terminal window, I am running selenium-server-andalone-2.47.1.jar with Java 7. I do have Firefox installed on my computer (it blankly starts when the test is run), and my computer is running OS 10.10.5.
This is what happens when I start the test runner:
$ wdio wdio.conf.js
=======================================================================================
Selenium 2.0/webdriver protocol bindings implementation with helper commands in nodejs.
For a complete list of commands, visit http://webdriver.io/docs.html.
=======================================================================================
[18:17:22]: SET SESSION ID 46731149-79aa-412e-b9b5-3d32e75dbc8d
[18:17:22]: RESULT {"platform":"MAC","javascriptEnabled":true,"acceptSslCerts":true,"browserName":"firefox","rotatable":false,"locationContextEnabled":true,"webdriver.remote.sessionid":"46731149-79aa-412e-b9b5-3d32e75dbc8d","version":"40.0.3","databaseEnabled":true,"cssSelectorsEnabled":true,"handlesAlerts":true,"webStorageEnabled":true,"nativeEvents":false,"applicationCacheEnabled":true,"takesScreenshot":true}
NoSessionIdError: A session id is required for this command but wasn't found in the response payload
at waitForVisible("h2.btn.btn-primary") - test2.js:21:14
/usr/local/lib/node_modules/webdriverio/node_modules/q/q.js:141
throw e;
^
NoSessionIdError: A session id is required for this command but wasn't found in the response payload
0 passing (3.90s)
$
I find this very strange and inexplicable, especially considering that it even prints the session ID.
Any ideas?
Please check out the docs on the wdio test runner. You don't need to create an instance using init on your own. The wdio test runner takes care on creating and ending the session for you.
Your example covers the standalone WebdriverIO usage (without testrunner). You can find examples which use wdio here.
To clarify that: there are two ways of using WebdriverIO. You can embed it in your test system by yourself (using it as standalone / or as a scraper ). Then you need to take care of things like create and end an instance or run those in parallel. The other way to use WebdriverIO is using its test runner called wdio. The testrunner takes a config file with a bunch of information on your test setup and spawns instances updates job information on Sauce Labs and so on.
Every Webdriver command gets executed asynchronously.
You properly called the done callback in afterEach and in your test it test, but forgot to do it in beforeEach:
beforeEach(function(done) {
client = webdriverio.remote({ desiredCapabilities: {browserName: 'firefox'} });
client.init(done);
});