How do I load a local json file in react native project at runtime where the local file will be a variable name?
Example:
This works
var data = require("../../0001.json");
I want this to work:
var path = "../../0001.json";
var data = require(path);
I'm open to alternatives to require.
TLDR: How do I open a file at runtime in react native. Load local data files as required by the app?
If you are using webpack, you could simply use require.ensure. But since all you want to load is JSON data, why don't simply use file API to read the JSON into a stream and then use JSON.parse?
Related
Im currently working on a new design for a mobile app (only frontend). In the project I need to use states to change the css of a button. If the button has changed, next time the app is refreshed the state should be as you left it.
That is why I have a locally stored JSON file that is structured the same as how the apps current database is. Reading it is no issue, but I can't get the writing to work.
How I read the JSON:
const jsonData = require('../data.json')
function GetBaseState(id){
console.log(jsonData.bases[id].state)
}
How would I go about changing that state in the JSON file?
In order to both of reading and writing Json file , you are able to use react-native-fs. For example by readFile method you can read json file and by writeFile method writing your json file in local storage.
react-native-fs have good documents that you are able to reading that for more information and usage.
I have a form on submit of the form I am receiving the json object after form submit. What I am trying is that I have a file data.json in my application folder in "/src/app/data.json". How can I write the data into the JSON file with Node.
Below is my code
Below is the code in my component.ts
savedatatojson(jsonobject){
// jsonobject is the json data
this.dataservice.savedata(jsonobject).subscribe(data => {
console.log(this.data)
})
}
Below is the code in my service file
public savedata(jsonobject):Observable<any>{
//code to be written
}
How do I save data to json file which I have obtained in my service file
You can't, web browsers don't have permissions to write to source files. There does exist a file system api, however this is non-standard and can only access a very limited location of files.
Instead you should either send the data to a database which later you can read and write to a file, or generate a file within the application which users could download for themselves to their own computer downloads folder. There is also the option to use serverless functions to update a remote file on a server, or for example a google sheet.
i am building an extension to parse json using vs code extension.
so my need is ,it should be able able to load .json file from a particular folder and iterate through content of the file.
Then it should allow user to select few keys from it make a new json file out of this and save it in any folder.
But i am not able to find any way to read and write files in "vs code extension".Could someone please help me.
If you want to read the current edit state of a file you can use the following API workspace function:
vscode.workspace.openTextDocument(uri).then((document) => {
let text = document.getText();
});
This will show you the current state of the file including unpersisted changes. document is of type TextDocument and has isDirty set to true if it has pending changes.
Since the extension runs in nodejs, you should be able to use any nodejs module built-in or installed by npm in the usual way.
For your purpose you will be OK with the built-in fs module: https://nodejs.org/dist/latest-v6.x/docs/api/fs.html
In your extension you will need to import the required module, so your code file should contain this:
let fs = require("fs");
and then use the methods in the usual way, eg. fs.fileReadSync( filename, encoding ) ...
Please not that there is one exception. If you install a nodejs module containing compiled, binary code, it will not run in the extension and instead you will see an error message saying something like %1 is not a valid Win32 application. Pure javascript modules are OK, though.
VSCode extensions are running in node.js. Therefore you can use any available node.js package/module within your extension. For instance, check out this question for reading JSON.
For JSON, you just need to require or import the JSON file, such as:
const jsonObject = require('./myJSONfile.json');
// do something
For JSON with comments, you can use node-jsonc-parser.
After the manipulation, you could use the fs module of nodej.js to write to the disk.
I have another question on this here Open a CSV file from S3 using Roo on Heroku but I'm not getting any bites - so a reword:
I have a CSV file in an S3 bucket
I want to read it using Roo in a Heroku based app (i.e. no local file access)
How do I open the CSV file from a stream?
Or is there a better tool for doing this?
I am using Rails 4, Ruby 2. Note I can successfuly open the CSV for reading if I post it from a form. How can I adapt this to snap the file from an S3 bucket?
Short answer - don't use Roo.
I ended up using the standard CSV commands, working with small CSV files you can very simply read the file contents into memory using something like this:
body = file.read
CSV.parse(body, col_sep: ",", headers: true) do |row|
row_hash = row.to_hash
field = row_hash["FieldName"]
reading a file passed in from a form, just reference the params:
file = params[:file]
body = file.read
To read in form S3 you can use the AWS gem:
s3 = AWS::S3.new(access_key_id: ENV['AWS_ACCESS_KEY_ID'], secret_access_key: ENV['AWS_SECRET_ACCESS_KEY'])
bucket = s3.buckets['BUCKET_NAME']
# check each object in the bucket
bucket.objects.each do |obj|
import_file = obj.key
body = obj.read
# call the same style import code as above...
end
I put some code together based on this:
Make Remote Files Local With Ruby Tempfile
and Roo seems to work OK when handed a temp file. I couldn't get it to work with S3 directly. I don't particularly like the copy approach, but my processing runs on delayed job, and I want to keep the Roo features a little more than I dislike the file copy. Plain CSV files work without fishing out the encoding info, but XLS files would not.
In a very simple first AIR application (I'm using Flash Builder 4.5), I am trying to accomplish the following on my MacBook:
Read a local file (JSON format) into the AIR app.
Parse through the file.
Display some selected contents in a grid.
That's it.
I've found an example that does some simple JSON parsing in Flex, but the problem is that it loads the JSON source from a remote web site.
So do I need to load any file-specific libraries to make this work in AIR? Or can I simply refer to the file by using the Mac file-path? I just want the local file to be the JSON source. The parsing is already taken care of.
You can use FileStream like:
var myFile:File = File.documentsDirectory.resolvePath("AIR Test/test.txt");
var myFileStream:FileStream = new FileStream();
myFileStream.open(myFile, FileMode.READ);
var yourJSONdata:String = myFileStream.readUTFBytes(myFileStream.bytesAvailable);
myFileStream.close();
Initializing a FileStream object, and opening and closing files