I'm trying to create an npm package called loca-mapper and for some reason it doesn't run when I include in my scripts: map: loca-mapper and launch npm run map, but it behaves correctly if you:
cd node_modules/loca-mapper
npm i (after all some dependencies won't be there due to the auto-resolve)
node ./index.js
What i get is an error message as follows:
/Users/{USER}/{PATH_TO_PROJECT}/node_modules/.bin/loca-mapper: line 1: syntax error near unexpected token `('
/Users/{USER}/{PATH_TO_PROJECT}/node_modules/.bin/loca-mapper: line 1: `const { getData } = require("./getLanguages/getLanguages.js");'
The content of my index.js is structured like this:
const { getData } = require("./getLanguages/getLanguages.js");
const { getConfig } = require("./utils/getConfig");
getData(getConfig());
Adding #!/usr/bin/env node at the beginning of the file would solve the issue.
#!/usr/bin/env node
const { getData } = require("./getLanguages/getLanguages.js");
const { getConfig } = require("./utils/getConfig");
getData(getConfig());
I'm building a node.js application using worker_threads under the hood. In the script file, called worker.ts, I cannot use the import statement because Node throws an error. So I'm importing the needed packages like this:
const { parentPort } = require('worker_threads')
parentPort.on('message', (data) => {
//Non relevant code
})
However, despite the code actually working, the following error is displayed since there is neither an import nor an export statement:
'worker.ts' cannot be compiled under '--isolatedModules' because it is considered a global script file.
How can I solve the issue?
Using the CodeSandbox link that you provided as a reference, I'll explain the changes that need to be made in both TypeScript modules in order for compilation to succeed and for the program to execute successfully:
./src/index.ts:
// Use import statements: TypeScript will transform them into "require" calls
// because you are targeting CommonJS in your TSConfig
import {Worker} from 'worker_threads';
import * as path from 'path';
const worker = new Worker(path.resolve(__dirname, './worker.js'));
/* ^^^
It is important to use the path of the **COMPILED** file,
and the extension of the compiled file will be ".js" */
worker.on('message', (data) => console.log('Main: ' + data));
worker.postMessage('Hello!');
./src/worker.ts:
// Again, use import statement
import {parentPort} from 'worker_threads';
parentPort.on('message', (data) => {
console.log('Worker: ' + data);
setTimeout(() => parentPort.postMessage(data), 1000);
});
Run:
# $ cd path/to/project/dir
$ tsc && node dist/index.js
Worker: Hello!
Main: Hello!
guys
I am learning redux, and try to run a very simple example code in node.js environment. I got the following error when I try to use :
import { createSlice, configureStore } from '#reduxjs/toolkit' .
The errors is:
import { createSlice, configureStore } from '#reduxjs/toolkit'
^^^^^^^^^^^
SyntaxError: Named export 'createSlice' not found. The requested module '#reduxjs/toolkit' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:
import pkg from '#reduxjs/toolkit';
const { createSlice, configureStore } = pkg;
at ModuleJob._instantiate (internal/modules/esm/module_job.js:120:21)
at async ModuleJob.run (internal/modules/esm/module_job.js:165:5)
at async Loader.import (internal/modules/esm/loader.js:177:24)
at async Object.loadESM (internal/process/esm_loader.js:68:5)
If I use import like what the error tip says:
import pkg from '#reduxjs/toolkit';
const { createSlice, configureStore } = pkg;
All is OK.
What I want to ask is:
It gives me a wrong example in the official website of Redux? Or Just I run the example with a wrong way?
The following is the detail information.
My Node.js version is: v14.17.3
1 Init a node project:
mkdir redux_01
cd redux_01
yarn init
yarn add #reduxjs/toolkit
2 Modify the 'package.json', add a line in it:
"type":"module"
3 Create a file 'index.js' with the "Redux Toolkit Example" code parsed from https://redux.js.org/introduction/getting-started.
import { createSlice, configureStore } from '#reduxjs/toolkit'
const counterSlice = createSlice({
name: 'counter',
initialState: {
value: 0
},
reducers: {
incremented: state => {
// Redux Toolkit allows us to write "mutating" logic in reducers. It
// doesn't actually mutate the state because it uses the Immer library,
// which detects changes to a "draft state" and produces a brand new
// immutable state based off those changes
state.value += 1
},
decremented: state => {
state.value -= 1
}
}
})
export const { incremented, decremented } = counterSlice.actions
const store = configureStore({
reducer: counterSlice.reducer
})
// Can still subscribe to the store
store.subscribe(() => console.log(store.getState()))
// Still pass action objects to `dispatch`, but they're created for us
store.dispatch(incremented())
// {value: 1}
store.dispatch(incremented())
// {value: 2}
store.dispatch(decremented())
// {value: 1}
4 Now I run it like this:
node index.js
I then got that error message that I just mentioned.
The reason for the error is explained here:
https://lightrun.com/answers/reduxjs-redux-toolkit-cannot-import-redux-toolkit-from-a-nodejs-esm-module "here"
solution:
import * as toolkitRaw from '#reduxjs/toolkit';
const { createSlice,configureStore } = toolkitRaw.default ?? toolkitRaw;
or in Typescript:
import * as toolkitRaw from '#reduxjs/toolkit';
I'm trying to execute prerender.ts as seen here to prerender my Angular code, but when I try and execute it using ts-node prerender.ts, I get the error:
import 'zone.js/dist/zone-node';
^^^^^^
SyntaxError: Cannot use import statement outside a module
at Module._compile (internal/modules/cjs/loader.js:892:18)
What is the proper way to execute this from NodeJS? Here is what prerender.ts looks like:
import 'zone.js/dist/zone-node';
import * as path from 'path';
import * as fs from 'fs';
import { enableProdMode } from '#angular/core';
import { renderModuleFactory } from '#angular/platform-server';
import { AppPrerenderModuleNgFactory } from './dist-prerender/main.bundle';
const distFolder = './dist';
const index = fs
.readFileSync(path.resolve(__dirname, `${distFolder}/index.html`), 'utf8')
.toString();
// we could automate this based on the app.routes.ts file but
// to keep it simple let's just create an array with the routes we want
// to prerender
const paths = [
'/about',
'/brews',
'/consultancy'];
enableProdMode();
// for every route render the html and save it in the correct folder
paths.forEach(p => renderToHtml(p, distFolder + p));
// don't forget to overwrite the index.html as well
renderToHtml('/index.html', distFolder);
function renderToHtml(url: string, folderPath: string): void {
// Render the module with the correct url just
// as the server would do
renderModuleFactory(AppPrerenderModuleNgFactory, {
url,
document: index
}).then(html => {
// create the route directory
if (url !== '/index.html') {
fs.mkdirSync(folderPath);
}
fs.writeFile(folderPath + '/index.html', html, (err => {
if (err) {
throw err;
}
console.log(`success`);
});
});
}
Update: I found that if I used tsc to transpile prerender.ts to JavaScript first and then executed that with node, I could get past this error. However, I started getting an error which I think is indicative of this code not running within the context of ngZone. So the code is still not right.
As stated here:
Current node.js stable releases do not support ES modules. Additionally, ts-node does not have the required hooks into node.js to support ES modules. You will need to set "module": "commonjs" in your tsconfig.json for your code to work.
Thus, pass below compiler option:
ts-node --compiler-options '{"module": "commonjs"}' prerender.ts
Of course, you can just include "module": "commonjs" in your (root) tsconfig.json file under "compilerOptions". This way you only have to execute:
ts-node prerender.ts
How to set what would otherwise be command-line arguments to node for a NodeJS process run from a launcher script? (The sh/CMD scripts npm places into node_modules/.bin.)
Plenty of NodeJS libraries / frameworks come with their own runner script, e.g. zeit/micro or moleculer that's usually executed from a npm script. This presents a problem in development, since in my case I want to do the equivalent of:
node --inspect -r ts-node/register -r dotenv-safe/config src/index.ts
(Except, of course, that does nothing since index.ts just exports something for the runner to pick up.)
Is there some "clean", preferably generic (i.e. not specific to a given framework's runner exposing those command line params) way that I'm missing to do this, ideally one that works as a npm script? The only thing that seems like it would work would be for e.g. micro:
node-dev -r ts-node/register ./node_modules/micro-dev/bin/micro-dev.js ./src/index.ts
which is kind of a mouthful from the Redundant Department of Redundancy Department and seems to obviate the point of having those launcher scripts. (It also won't work if the runner spawns other Node processes, but that's not a problem I'm actually having.) I'd like to not have to duplicate what the launcher scripts are already doing. I'm also aware of npx having --node-arg but npx is a whole another can of worms. (On Windows it's five seconds of startup time and one spurious error message just to run a script I already have installed; it also won't find an already installed package if it can't find its .cmd launcher script, e.g. when using Docker to run the dev environment. In short I'd rather not use npx for this.)
To clear up the confusion that seems to crop up in the comments: I want to override the command line parameters that affect the behaviour of the NodeJS runtime itself executing the runner script, not pass parameters to the script itself or to my code. That is, the options listed here: https://nodejs.org/api/cli.html
One option is to write a little wrapper script that uses the current process execPath to run child_process.execFile.
So the sample here is to be able to do
node --expose-http2 --zero-fill-buffers -r ./some-module.js ./test.js
but not actually write that out, instead have wrap.js inject the args:
node ./wrap.js ./test.js
I tested running this via npm in a package.json, and it works fine. I tested that it was working by having some-module.js stick a value on the global object, and then logging it in test.js.
Files involved:
wrap.js
const child_process = require('child_process');
const nodeArgs = ['--expose-http2', '--zero-fill-buffers', '-r', './some-module.js'];
const runTarget = process.argv[2];
console.log('going to wrap', runTarget, 'with', nodeArgs);
const finalArgs = nodeArgs.concat(runTarget).concat(process.argv.slice(2));
const child = child_process.execFile(
process.execPath,
finalArgs,
{
env: process.env,
cwd: process.cwd(),
stdio: 'inherit'
}, (e, stdout, stderr) => {
console.log('process completed');
if (e) {
process.emit('uncaughtException', e);
}
});
child.stdout.pipe(process.stdout);
child.stderr.pipe(process.stderr);
and
some-module.js
global.testval = 2;
and
test.js
console.log('hi guys, did the wrap work?', global.testval)
EDIT: So upon further thought, this solution really only satisfies wrapping the initial runner. But most tools, such as mocha re-spawn a sub process which would then lose this effect. To really get the job done, you can proxy each of the child process calls and somewhat enforce that calls to spawn and such also include your args.
I rewrote the code to reflect this. Here's a new setup:
package.json
{
"scripts": {
"test": "node -r ./ensure-wrapped.js node_modules/mocha/$(npm view mocha bin.mocha) ./test.js"
},
"dependencies": {
"mocha": "^5.1.0"
}
}
ensure-wrapped.js
const child_process = require('child_process');
// up here we can require code or do whatever we want;
global.testvalue = 'hi there'
const customParams = ['--zero-fill-buffers'];
// the code below injects itself into any child process's spawn/fork/exec calls
// so that it propogates
const matchNodeRe = /((:?\s|^|\/)node(:?(:?\.exe)|(:?\.js)|(:?\s+)|$))/;
const ensureWrappedLocation = __filename;
const injectArgsAndAddToParamsIfPathMatchesNode = (cmd, args, params) => {
params.unshift(...customParams);
params.unshift(args);
if (!Array.isArray(args)) { // all child_proc functions do [] optionally, then other params
args = []
params.unshift(args);
}
if (!matchNodeRe.test(cmd)) {
return params;
}
args.unshift(ensureWrappedLocation);
args.unshift('-r');
return params;
}
child_process._exec = child_process.exec;
child_process.exec = (cmd, ...params) => {
// replace node.js node.exe or /path/to/node to inject -r ensure-wrapped.js ...args..
// leaves alone exec if it isn't calling node
cmd = cmd.replace(matchNodeRe, '$1 -r ' + ensureWrappedLocation + ' ');
return child_process._exec(cmd, ...params)
}
child_process._execFile = child_process.execFile;
child_process.execFile = (path, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(path, args, params);
return child_process._execFile(path, ...params)
}
child_process._execFileSync = child_process.execFileSync;
child_process.execFileSync = (path, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(path, args, params);
return child_process._execFileSync(path, ...params);
}
child_process._execSync = child_process.execSync;
child_process.execSync = (cmd, ...params) => {
cmd = cmd.replace(matchNodeRe, '$1 -r ' + ensureWrappedLocation + ' ');
return child_process._exec(bin, ...args)
}
child_process._fork = child_process.fork;
child_process.fork = (module, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(process.execPath, args, params);
return child_process._fork(module, ...params);
}
child_process._spawn = child_process.spawn;
child_process.spawn = (cmd, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(cmd, args, params);
return child_process._spawn(cmd, ...params)
}
child_process._spawnSync = child_process.spawnSync;
child_process.spawnSync = (cmd, args, ...params) => {
params = injectArgsAndAddToParamsIfPathMatchesNode(cmd, args, params);
return child_process._spawnSync(cmd, ...params);
}
test.js
describe('test', () => {
it('should have the global value pulled in by some-module.js', (done) => {
if (global.testvalue !== 'hi there') {
done(new Error('test value was not globally set'))
}
return done();
})
})
Please never put code like this into a node module that's published. modifying the global library functions is pretty bad.
Everything passed in the command line AFTER your nodejs application is parsed into an array called process.argv. So...
node myapp.js foo bar hello 5000
In your nodejs code...
const args = process.argv;
console.log(args[0]);
console.log(args[1]);
console.log(args[2]);
console.log(args[3]);
would yield...
foo
bar
hello
5000
I didnt get clear scenario of your problem,but as your question title ,we can execute the any cmd command from nodejs using npm libraries like:
import Promise from 'bluebird'
import cmd from 'node-cmd'
const getAsync = Promise.promisify(cmd.get, { multiArgs: true, context: cmd })
getAsync('node -v').then(data => {
console.log('cmd data', data)
}).catch(err => {
console.log('cmd err', err)
})