Populate Javascript Array with JSON Data - javascript

I am attempting to load a large set of JSON files into an array to be referenced later but Node keeps stating they're undefined. I have code along the lines of:
var myarray = [];
(...)
var loading_num = 001; // will be incremented in a loop to load data
myarray[loading_num] = fs.readFileSync("data/" + loading_num);
(...)
var reference_num = "001"; // the number being used to pull the appropriate record
(...)
console.log(myarray[reference_num].name); // just testing to attempt to decipher why it doesn't work, I'll actually be using the data obviously
Each JSON file does have a value named name and I have not implemented logic to load all of them yet as I am still just trying to get one to work.
Am I misunderstading something about Javascript arrays or objects? What am I doing wrong? There's a lot of files and they can vary in number so I have to load them in some similar fashion.

You should parse the file contents so the raw data is converted into JavaScript objects.
myarray[001] = JSON.parse(fs.readFileSync("data/001"));

First of all. fs.readFileSync reads arbitrary files. If you know your file is JSON and you want to convert it to js you need to parse it using JSON.parse.
Then 001 is 1 if you want it to be a string wrap it with quotes '001'
Array indices starts from 0.
var myarray = [];
myarray.push(JSON.parse(fs.readFileSync("data/001")));
console.log(myarray[0].name);
Or
var myarray = {}; // use object
myarray['001'] = JSON.parse(fs.readFileSync("data/001"));
var reference_num = "001";
console.log(myarray[reference_num].name);

Related

json.dumps returns the objects as a string instead of a JSON object

In the views.py:
data1 = Inventory.objects.values_list('product_number','amount') data = json.dumps(list(data1), cls=DjangoJSONEncoder).
I pass data as context to the html file.
In the HTML file, Using JS I access the JSON object with this code:
{{ data|json_script:"hello-data" }}
<script type="text/javascript">
var data = JSON.parse(document.getElementById('hello-data').textContent);
document.getElementById('id_line_one').onchange = function(event){
console.log(typeof data)
alert(data);
document.getElementById('id_line_one_unit_price').value = data[this.value];
};
</script>
I expect the var data to be a dictionary but it seems to be a String. Object.fromEntries is not working and I get the error Uncaught TypeError: Iterator value [ is not an entry object at Function.fromEntries (<anonymous>).
JSON.parse is removing the double quotation and I get [[1, 56000], [2, 55000]] but I am not able to access it as a dictionary. Whenever I use the index to access it, It returns the single characters as output instead of thinking of it as a dict object. How can I convert it into a dictionary? Thanks
The problem is that you are obtaining a list from the following line:
data1 = list(Inventory.objects.values_list('product_number','amount'))
Hence, you are just converting a list to JSON and, then, parsing this JSON, which yields a list.
Try to use the following instead:
from django.core.serializers.json import DjangoJSONEncoder
from django.core import serializers
data_obj_model = Inventory.objects.all()
data1=serializers.serialize('json', data_obj_model, cls=DjangoJSONEncoder)
Then, you can access, in your JavaScript code, all the fields of the model using data["fields"].field_of_interest.
Or you can also create a custom dictionary with the two fields you were interested in as follows:
data1 = dict(Inventory.objects.values_list('product_number','amount'))
This could be used as a dictionary in the JavaScript after parsing it.

Insert data in Firebase in Reactjs

During storing an object to my firebase, I am expecting the structure as image below, but what I get was a generated running number as a key. This is my code to store an object to firebase
var location = [];
location.push({
ms_jhr_1 : {
name: value
},
...
});
const a = firebase.database().ref('Food/'+id);
a.set(location);
How do I keep my structure without generate the running number?
The problem is you are using an array to store your data and then setting that array in firebase. To get the expected result you have to modify your code a little bit.
Here use this and remove other code
const a = firebase.database().ref('Food/'+id);
a.set(ms_jhr_1);
So you just need to pass the object you want to store under that id and not the whole array.
Note:- If you want to store multiple entries under one id then you have to push all those entries in an Object and not in array.
So it will look something like this
var location = {};
Now use for loop to insert all your data into this object (Remember, you are adding objects inside an object). You don't need array. Because in firebase data is stored in JSON tree format.
Hope it helps.

matching content of a file

I´m having a problem with a javascript function.
The idea is read the content of a file with javascript. Everything is working ok, I can see the content of the file, just now I want to organize the content.
And what I meant with organize is:
My file have a lot of strings, for example: tel#01234567#tel tel#01456789#tel dept#level1#dept dept#level4#dept.....
And everything is a line of strings, and at the end is that all what I see...
My goal is, when I read the file, at the end it have to show something like this:
Tel: 01234567
01456789
Dept: Level1
Level2
There is a way to have something like that?
function loaded(evt)
{
// Obtain the read file data
var fileString = evt.target.result;
document.getElementById('output').innerHTML = fileString;
}
So basically your file has attributes and data for the respective attribute surrounded by the attribute name + #?
The easiest thing would be to have the file in a common format for data, e.q. JSON. Then you could just use the attributes from the object you get by JSON.parse();
However, if you cannot change the file structure you will have to programm something that splits your string into the desired parts and creates an object out of the attributes to work with.
For the string you presented you could do one string.split(" ") to get every attribute singled out, resulting in an array like this:
Array [ "tel#01234567#tel", "tel#01456789#tel", "dept#level1#dept", "dept#level4#dept" ]
Afterwards you can iterate over the array and string.split("#") again for each element which gives you this:
array[0].split("#");
Array [ "tel", "01234567", "tel" ]
Then you can use the first index of the array as attribute name and the second one as its data. You could put that into an object and afterwards refer from the attribute straight to the data:
var string = "tel#01234567#tel tel#01456789#tel dept#level1#dept dept#level4#dept";
var array = string.split(" ");
var dataObject = {};
for(var i in array){
var element = array[i].split("#");
if(dataObject.hasOwnProperty(element[0])){
dataObject[element[0]].push(element[1]);
}else{
dataObject[element[0]] = [element[1]];
}
}
In the end you have an object that has all the attributes as its properties and the corresponding data stored in an array for each property. With that you should be able to work right? :)
When you read the file in you could use JS split to separate the content based on the delimiters.
Check it out here: http://www.w3schools.com/jsref/jsref_split.asp

JSON decode list of lists in Django Python

I have a list of lists (e.g. [[1,2],[3,4]]) passed from a Django view to a javascript variable and submitted with jQuery. I need to parse that variable to pull indices. The basic process is:
Add as context variable (python):
resultMsgList.append(msg)
resultMsgListJson=json.dumps(resultMsgList)
resultDict['resultMsgListJson']= resultMsgListJson
Javascript:
var resultMsgList = {{resultMsgListJson}};
var data = {'resultMsgList':resultMsgList};
$.post(URL, data, function(result){
});
Google Console gives me:
Javascript:
var resultMsgList = [["View \"S03_2005_LUZ_140814_105049_with_geom\" was successfully created!", "luz_mapfile_scen_tdm_140814_105049", "S03_2005_LUZ_140814_105049_with_geom", "C:/djangoProjects/web_output/mapfiles/ATLANTA/luz_mapfile_scen_tdm_140814_105049.map", [25, 50, 498.26708421479, 131137.057816715]]];
I copied this result to a validator, which states it is correct JSON.
The post gives me:
resultMsgList[0][]:View "S03_2005_LUZ_140814_105049_with_geom" was successfully created!
resultMsgList[0][]:luz_mapfile_scen_tdm_140814_105049
resultMsgList[0][]:S03_2005_LUZ_140814_105049_with_geom
resultMsgList[0][]:C:/djangoProjects/web_output/mapfiles/ATLANTA/luz_mapfile_scen_tdm_140814_105049.map
resultMsgList[0][4][]:25
resultMsgList[0][4][]:50
resultMsgList[0][4][]:498.26708421479
resultMsgList[0][4][]:131137.057816715
I need to get elements from this list. I currently have (python):
resultMsgListContext = request.POST.get('resultMsgListJson','')
resultMsgListContext = json.loads(resultMsgListContext)
oldMapfileName=resultMsgListContext[0][2] (+ a number of similar statements)
According to this post I then need to decode the variable in python with json.loads(), but it says there is no JSON object to be decoded. Based on the examples in the Python docs, I'm not sure why this doesn't work.
I believe the problem is that it is viewing the entire resultMsgList as a string, substantiated by the fact that there is a u' xxxxx ' in the result. That's why it is saying index out of range because you're trying to access a 2D array when it is still a string. You have to convert it to an array of strings by using json.loads.
In javascript, try passing
var data = {'resultMsgListJson':resultMsgList};
instead of
var data = {'resultMsgListJson': resultMsgListJson};
resultMsgListJson isn't a javascript variable that's defined at that point, it might be getting evaluated to undefined.
In general, in python, print the contents of resultMsgListContext before trying to do json.loads on it so you can see exactly what you're trying to parse.

Can I convert a json input to a list of objects within jquery?

I'm new to jQuery and just playing for fun. I have some code that I want to try to modify for my needs but the current js file is getting its data from google spreadsheets and then returning each item as objects. I don't use json to pass data from my server to jQuery so I'm wondering how I can convert json to objects.
The current way its doing it is(tabletop is the name of their js program that gets data from google docs):
Tabletop.init({
key: timelineConfig.key,
callback: setupTimeline,
wanted: [timelineConfig.sheetName],
postProcess: function(el){
//alert(el['photourl']);
el['timestamp'] = Date.parse(el['date']);
el['display_date'] = el['displaydate'];
el['read_more_url'] = el['readmoreurl'];
el['photo_url'] = el['photourl'];
}
});
I have added alerts all over the file and I think this is the area that gets the data and passes it on. I was thinking of trying to replace items in their object with objects from my json and see if it changes anything, but I'm unsure. Typrically I pass individual items via json,hashmaps, and lists, not sure how it works with objects or how to access objects(I simply call url's that I create for the requests, $("#user-history").load("/cooltimeline/{{ user.id }}");). But where do I start if I want to turn json data into objects?
If it helps, here's the demo of what I'm trying to do(but by having it use json data).
p.s. I'm really looking for the logic of how to complete what I'm trying to do and perhaps some ideas I'm missing so I can google them and learn.
Use use function JSON.parse(json) :) Or jQuery.parseJSON(json)
var json = '{"a":2}';
var object = JSON.parse(json);
alert(object.a);
You should see alert with message: 2
I don't realy know if I understand your comment, but maybe you want just do this:
postProcess: function(el){ //here el is JSON string
el = JSON.parse(el); // now el is an object
el.timestamp = Date.parse(el.date);
el.display_date = el.displaydate;
el.read_more_url = el.readmoreurl;
el.photo_url = el.photourl;
return el;
}
Btw. you do not need to use brackets on know property names without not standard names:
el['timestamp'] === el.timestamp
It will be easier if you paste your JSON

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