Will importing local json/text like the following I have written below be async or sync in Create-React-App?
import SampleLocalJson from './sample/sampleJson.json'
This depends on your environment. If you are using webpack >=v2.0.0 (which you probably do if the above line works) this will be done automatically by webpack json-loader during build time and is therefore sync.
If you are not on webpack >=v2.0.0 there can be multiple issues with directly importing json. Here is a good thread about it: How to import a json file in ecmascript 6?
UPDATE
If you are interested in lazy loading the json, there is support for that built in to webpack. They have a good example in their documentation on that.
This is handled by webpack during the build time. That JSON becomes part of your bundle file shipped to the browser.
Related
How VSCode parses json files like language-configuration.json that is used to describe language extensions? I see that these files contain comments and many, like typescript, contain trailing commans.
If such content is parsed using JSON.parse() the error will be raised.
I implement an extension that reads these config files and like to use the same parsing method that is used in vscode.
Thank you
I would assume they use the jsonc-parser - since it is written by one of the vscode team and has 3 million+ downloads a week.
npm package: jsonc-parser
I use it myself because I need to parse complicated custom settings that might have comments in them for example.
Add the package to your dependencies. npm install --save jsonc-parser
Then import it (I have it in a js extension for now):
const jsonc = require("jsonc-parser");
const rootNode = jsonc.parseTree(document.getText());
I'm stuck with fs module in angular 7 cause it is showing can't find module fs when I'm trying to write to json file. Please suggest me some alternatives for this.
No, there is no way. Angular is running in a browser, on a user pc or handheld or whatever. It would be a security problem if your angular app would have access to the file system.
Google is planning this at the moment, but it's not standard.
What you can do: You can read jsons files from server via http.get request or write json to the server via http.post requests.
angular will work together with every backend server : java-spring-boot or php or node.js, ...
In node.js you will find your fs.
P.S.: the npm and node_module in your angular app only exists during development. After compiling you get plain html, js and css.
I'm trying to require some JSON files in my React app (based on CRA 3.01 with Typescript).
The normal const obj = require('./path/file.json') would work if my files had a .json extension - however, these files have .md for 'metadata' and a couple other extensions, and the standard require isn't working. The files are from a tool, so changing to .json isn't a practical option.
Doing some research, it seems the approach is to use the webpack json-loader module (the webpack json-loader docs says that working with different file extensions is the main reason for using the module). I found an example and am using this:
const context = require.context(
"json-loader!./metadata",
true,
/^\.\/.*\.md$/
);
const metadata = context("./foo.md");
I've got a minimum reproduction here (see App.tsx):
https://github.com/ericsolberg/testjson
It seems that this is correctly using the json-loader, and finding the file correctly. However, I'm getting a syntax error:
Error: Module build failed (from ./node_modules/json-loader/index.js):
SyntaxError: Unexpected token m in JSON at position 0
at JSON.parse (<anonymous>)
at Object.module.exports (/Users/***/projects/jsontest/node_modules/json-loader/index.js:4:49)
I did some research on this error, and believe the problem is that the file is being parsed twice - first by the loader configured by CreateCreactApp's default webpack config, then by the specified JSON loader.
I don't want to eject my CRA app to modify the webpack config, and would like to avoid a re-wire hack (and whatever other issues that introduces) ... does anyone know of a way to load JSON files in a CRA app, if these files don't have a JSON extension?
Here's the solution that ended up working for me.
I could eject my project, of course, and customize the webpack config to load JSON files with other extensions. It may be possible to make a rewire hack work as well.
But I realized that when I require a file that is not one of the extensions recognized by CRA's config, it instead copies that file into the build, and require('file.ext') returns the URL of the file. So I'm using axios to load the file. This means a trip to the server for something that could be done statically, but for where I'm taking this project that is actually OK (eventually it will load metadata from a server anyway).
I came across two ways to import local json files to my code.
Using angulars http get.
Thats well known for loading json input. You can switch easily from remote to local json files.
Typescript require
Another way to load json in typescript files is via require. This is simple as I don't have to deal with Promises/Observables. I just include them like this:
data: any = require('assets/json/my.json');
I want to know something about the advantages and disadvantages between these two approaches. Is there a prefered way and why?
Hi it depends on your requirement.
If your file is constant, will not be changed then it is best option is to use .require()
- .require() will cache your file, and when you import again it will give the cached file, so it might be bad option you want current time data because you will not get the updated data from that file
But if your file is getting updated then you have to use HTTP.
I know I can require a file in ES6 like this:
require('./config/auth');
When I try to do this
require('./config/');
I get: Module not found: Error: Cannot resolve directory './config'. Why does this happen? How can I require a directory?
First of all, your requires are in NodeJS/io.js syntax, module in ES6 syntax looks like this:
import "./config/auth";
Or if you want to load something from it:
import authenticate from "./config/auth";
You can't load whole directories at once, but in Node/io.js you can create a module and then load that.
Note that as a workaround you can load a single file that in turn loads multiple files and returns their results. There is also work in progress on an asynchronous loader but that changes so often it's hard to keep track so I wouldn't rely on it just yet.
I personally use a package called require-dir. This should work for you:
import requireDir from 'require-dir';
requireDir('./config');