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I have a separate .json file, I need to iterate over the file or read through the file and do some stuff. How exactly do I do this in Javascript?

I have a folder with an html, css, json, and js file. The js file are a list of person's and what they do. I need to analyze the json file contents using javacript. I know that in C or C++ you can open the file for reading and analyze it, then close it. So, how do I do this in Javascript? And do I need to add the name of the JSON array in the .json file, or should i leave the contents as it is?
JSON screenshot image
Nothing online have worked thus far. Hopefully Stackoverflow can help.

Let's assume you're using nodeJS, you can import the json file using require .
After you've imported the json file, you can access the object as it would be a JS object.
const jsonFile = require("./pathtofile.json")
for(let obj in jsonFile) {
console.log(obj)
}

Why can't this code access my JSON file in netbeans?

So I am trying to learn Javascript. I created a JSON file called "Ancest.json". Then, in a new file on netbeans I tried to execute this code accessing that file:
var ancestry = JSON.parse(Ancest);
console.log(ancestry.length);
I am getting a rejection saying "Ancest is not defined".
What am I doing wrong? Attached is a screen shot. Thank you for your time.

JSON.parse method accepts a string which is the JSON object to be parsed into a JavaScript object.
You need to get the content of the file or to move the content of your JSON file into a string variable in the js file. Then you can parse it:
console.log(JSON.parse('{ "a": "test" }'));
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse

You need to assign a string Ancest or var Ancest = './Ancest.json'; Depending on the location and path of Ancest.json, you may have to put in the full path or linked path if the .js file exists in the same path. Also put the path in single quote or double quote. Make sure you have access to read the file.
It also needs correct file system permissions. This is all contingent on who this js is running as, delegate permissions on the parent directories, etc, etc. Chances are permissions are okay for read.

Upload PSD/any photoshop file via HTML File Input not working

I am trying to upload a file using HTML File Input ().
But even if I pass to it's accept property valid mimetypes for photoshop files e.g. application/psd/application/photoshop/application/x-psd/image/psd/image/x-psd etc. it doesn't recognize the type and doesn't show corresponding files in the explorer.
But then I try to use All Files and get the File right. But there is no FileType in it. It's showing "" empty string like this. For which I am failing to identify the file in the server.
I tried a lot to find a solution for this but failed. Am I missing something or HTML File Input doesn't support that? Or I'll have to do something else for that?
Is there any other way of getting around with that?

Displaying a generated JSON file on a simple website

I have a Java tool, which schedules a task every 24 hours and writes the result in a result.json file. Now I want to display this result.json file on a simple website, but I know that it's not natively possible with JavaScript to access local files. But what other, simple ways exist for this problem? I try to avoid a webservice to keep the scheduling-program and the website on the same server.
Thanks!

You can use the object FileReader for read the file stream from your system and gets the JSON file in a string, later use JSON.parse() to get the JSON in JS object and iterate over it for pretty representing in document DOM, or you can print the string in the HTML without parse to JS object.
Here there are a very completely example of FileReader.

How do you check whether a CSV file is corrupted in PHP and/or Javascript?

I'm making an HTML5/jQuery/PHP app which involves uploading CSV files (via a drag and drop), and processing them to a MySQL database. So far, I can upload the files, and I know how to read them into a database.
My question: I am wondering if it is possible to detect whether a CSV file is in a corrupted format by PHP or Javascript/jQuery? For example, I can rename somefile.png (an image) to somefile.csv, and it still gets uploaded. If I open up the renamed file in Notepad++, all I see is garbage, which is expected.
I would like to do this on the clientside, so I can alert the user (via JQuery) whether the file is in a corrupted format. I'd also like to check on the serverside (via PHP) before I start iterating over each CSV file for db processing.
My first thoughts would be to use regular expressions, but I am unsure how to make ones for this particular problem. I know the basics of regular expressions, but haven't really used them in advanced settings before.

First of all you should check content-type of picked file, it should be "text/csv". At the server-side you can check file via fgetscsv PHP function (http://php.net/manual/function.fgetcsv.php) (catch null or false on error)

You don't want to be validating it if you're going to be reading it right after. Just read it in and catch any errors as you read. That way you come to know whether file is valid or corrupt.