I'm trying to access the decode() method in the jsQR module.
I found an example that called decode() directly but that was from an HTML file, not nodejs.
In visual code I see this...
I know that the default export is defined in index.d.ts but is there anyway of importing the other classes/functions on the rest of the dist folder?
I've tried to import using require("jsqr/decoder") and require("jsqr/decoder/decode") to no avail.
EDIT
To be clear, I don't want jsQR, the default export. That deals with images. I'm trying to explicitly call the decode() method in the pic which accepts a BitMatrix
There are no limitations in what you can require from node_modules. So, with your case it should look like:
TypeScript\ESM Modules:
import { decode } from 'jsqr/dist/decoder/decoder';
CommonJS:
const { decode } = require('jsqr/dist/decoder/decoder');
UPD: If you take a look into dist folder for jsqr package, you can find that there are only d.ts files. Which means that you can not import it from there.
But, you can find an actual export of the module here:
Which means that you should able to import it from jsqr:
const { decode } = require('jsqr');
Related
I want to organize my firebase cloud functions in specific files,
and currently, I have these 3:
index.ts
crypto.ts
webscrape.ts
Inside of these files, I have functions that use specific dependencies that are needed nowhere else.
For example, in crypto.ts I need the crypto-js package to encrypt some user data and store it into the database.
So I am importing it like so:
import * as CryptoJS from "crypto-js";
as advised in https://firebase.google.com/docs/functions/handle-dependencies#typescript
On the other hand, when I try to import puppeteer into webscrape.ts like this:
import * as puppeteer from"puppeteer-extra";
then calling puppeteer.launch(); gives me an error :
Property 'launch' does not exist on type 'typeof import("c:/Users/username/Desktop/project/firebasee/functions/node_modules/puppeteer-extra/dist/index")'
and it only works when I do const puppeteer = require("puppeteer-extra");
What's the difference here?
My goal is to keep the dependencies of each functions and file/module as small as possible because I assume that this will also keep the size of each function container small (Is that even true?)
I didn't want to import everything to index.ts even when I trigger a function, that doesn't use this dependency at all.
So what is the correct way of handling these dependencies?
Thanks!
The following import will get the default export from that package.
import puppeteer from "puppeteer-extra"
I looked for the default export in the Github repository and found that.
const defaultExport: PuppeteerExtra = (() => {
return new PuppeteerExtra(...requireVanillaPuppeteer())
})()
export default defaultExport
They have mentioned both ES6 import and require methods here.
// javascript import
const puppeteer = require('puppeteer-extra')
// typescript/es6 module import
import puppeteer from 'puppeteer-extra'
You can read more about import on MDN.
trying to use passport-custom and the very first line, from pseudocode at npmjs, errors out:
import passportCustom from 'passport-custom';
The is no default import in index.js when I open it up under node_modules/passport-custom/lib
I must be missing something fundamental here, don't know what though
Try to use CommonJS const passportCustom = require("passport-custom") You probably have older version of Node.js which does not support ES6 modules.
There is no default export. So you will have to name the items you want to import (put them in curly braces).
//Example:
import { a,b,c,d} from 'youPackage';
//Your case:
import { passportCustom } from 'passport-custom';
Above are called named imports. When a package exports one item by default using: export default passportCustom ;, you could have use your code. You can access the code of the package to have a look for yourself.
I am having strange issues with Typescript when I import things from a file which exports them. Sometimes I will export a function, then import it to another file, then I use the function and it is not a function anymore. When I define the function in the same file, all of a sudden the function is a function?!?!?
Why would a function stop being a function when it is exported? I have had similar problems with classes too.
The hard part of this issue is I can't recreate a simple example because it only happens when I am using some kind of higher level package.
For example, I had a similar issue with sequelize-typescript here: my github issue with typescript-sequelize
Below is some codes showing off the basic issue I'm having with one of the decorators from InversifyJS.
container.ts
import {fluentProvide} from "inversify-binding-decorators";
export const provideSingleton = (identifier: any) => {
return fluentProvide(identifier)
.inSingletonScope()
.done(true);
};
test.service.ts
import {provideSingleton} from './container'
#provideSingleton(TYPES.TEST)
export default class TestService {}
The strangest thing is when I put the provideSingleton in the same file as the TestService, everything works!?!?!
Basically to recreate the issue, simply follow the example from here: inversify-binding-decorators - Using #provideFluent multiple times. However there is an issue with the example, so please see this issue: fluentProvide example needed. The above provideSingleton reflects the changes from that issue. Then you simply import the provideSingleton function from another file instead of defining it in the same like in the example.
Can anyone explain to me what I'm missing? Why oh why would certain exported items not bee seen as the type they are? Is there a step I'm not seeing that NodeJS takes to make the item actually exported and therefore different? Can I force the function to resolve as a function so it can be used as such?
ENV:
NodeJS: 10.9.0
Typescript: 3.0.1
Mac: 10.13.16
So it looks like you can get issues like this when NodeJS can't handle a recursive import. I'm not exactly sure how to check you are getting this error other than your symptoms are like what I stated above. Basically the recursion caused my function to not load and therefore undefined is not a function.
It would be easy to notice if you had code like so:
a.ts
import B from './b';
export default class A extends B {}
b.ts
import A from './a';
export default class B extends A {}
In my case, I think my function provideSingleton did not like the file I put it in because of some conflicting code in the file, which all I had was:
import {Container} from 'inversify';
import "reflect-metadata";
import {fluentProvide} from "inversify-binding-decorators";
const container = new Container();
function ProvideSingleton(identifier: any) {
return fluentProvide(identifier)
.inSingletonScope()
.done(true);
}
export {container, ProvideSingleton}
In the end, if this issue comes up, try another file for your function and pay good attention to how the order of the loading happens. Although NodeJS handles recursive imports most of the time, you can still trip it out.
I have the following reference import { STORE } from "../data/store"; It's part of a react project and works as expected.
However I need to run some code separately over STORE and accessed it the same way as it is in the react project, but ran via ts-node. When I try to access STORE by let data = STORE[videoId].labels;, with videoId set as "home" I get TypeError: Cannot read property 'home' of undefined.
Might anyone know what I'm missing --- must be something specific to ts-node...? Thanks!
In case someone arrives on this page because of imports issue, like I did, here's what my problem was:
I had three files : index.ts, File.json and File.ts
In index.ts:
import { thing } from "./File";
was working well in VS Code: I had auto-completion for thing and everything.
But when running ts-node index.ts, thing was undefined!
When I remembered that I had the json file, I just renamed File.ts to File.module.ts and changed the import to:
import { thing } from "./File.module";
and it was sorted.
It sounds like the property STORE is undefined..
If you change import { STORE } from "../data/store"; to import * as STORE from "../data/store" does it work?
I'm not sure if this extreme edge case or something but I cannot seem to find straight forward documentation on how to do this (or I'm just really not understanding what is available):
I am developing an ionic application and as part of that I need to use the ALKMaps JavaScript library (which is similar to Google Maps API). To do so, I created a local npm module and within that I created a alkmaps.d.ts file as recommended by https://www.typescriptlang.org/docs/handbook/declaration-files/by-example.html#objects-with-properties). However, I cannot seem to figure out how to properly import it into my angular code. The same document suggests that using <reference path=''> tags is not good but that is the only thing that seems to satisfy the tsc compiler.
My declaration file, alkmaps.d.ts, looks like (inside excluded for brevity):
declare namespace ALKMaps {
export class Map { ... }
...
}
And I was trying to import it into a file like:
import { ALKMaps } from 'alkmaps'; // Error: File '.../alkmaps.d.ts' is not a module
I also tried the following but got the same error.
import ALKMaps = require('alkmaps');
Using the reference tag seems to work within this module but then the project that utilizes this module still throws the "is not a module" error (that might warrant a separate question)
From https://github.com/Microsoft/TypeScript/issues/11420 I found the idea of using export = ALKMaps or export as namespace ALKMaps but adding those to my declaration file resulted in different errors instead.
Can anyone please explain in a straightforward way how to use declaration files representing external JS libraries in a typescript node module?
This is how I was able to get alkMaps into my Angular 2 app
Insert the script into the index.html file.
Declare an ALKMaps variable in the component that you are adding the map
imports .....
declare let ALKMaps : any;
#Component({
selector: 'show-map',
templateUrl: 'show-map.component.html'
})
export class ShowMapComponent implements Oninit{
map : any;
constructor() {
}
ngOnInit() {
ALKMaps.APIKey = "apiKey";
this.map = new ALKMaps.Map("map", {displayProjection: new ALKMaps.Projection("EPSG:4326")});
}
}
This will get the map to display and you can put different layers on the map, however the map does not display correctly. #Mike, if you were able to get further than this, will you please comment?
EDIT: The tiles on the image were elongated and not connected. After inspecting the css the main.css, after building, set a global property on the img element to:
img {
max-width:100%
}
The tiles for the map are originally set to 256% for the width. To correct the element, I changed the property for img in the style sheet.
show-map {
img {
max-width: 256%
}
}