I'm writing a node js program that does the below.
get the json.
parse it.
print to console.
Currently I'm able to do the above three things very smoothly. But my problem comes up here. I'm trying to convert a value from json to int. and below is my sample data.
{
"Items": [
{
"accountId": "12345",
"pin": "1234",
"userId": "user1",
"dueDate": "5/20/2017",
"_id": "2",
"dueAmount": "4000",
"totalBalance": "10000"
}
],
"Count": 1,
"ScannedCount": 4
}
and from the above json I'll need the dueAmount in int format so I tried the below code.
var userDueDate = JSON.stringify(res.Items[0].dueDate);
var userDueAmount = JSON.stringify(res.Items[0].dueAmount);
var userTotalBalance = JSON.stringify(res.Items[0].totalBalance);
var intUsingNumber = Number(userDueAmount);
var intUsingParseInt = parseInt(userDueAmount);
console.log('by using Number : ' + intUsingNumber + ' and the type is :' + (typeof intUsingNumber));
console.log('by using Parse : ' + intUsingParseInt + ' and the type is :' + (typeof intUsingParseInt));
and when I run this program I get the output as
by using Number : NaN and the type is :number
by using Parse : NaN and the type is :number
Where in I need to print 4000 instead of NaN.
Also, what I'm confused is, the type is showing it as a number, but the value is given as NaN.
Please let me know where am I going wrong and how can I fix it.
Thanks
JSON is a JS object wrapped as a string:
let json = "{"dueAmount":"4000"}" - is a JSON object,
let jsObj = {"dueAmount":"4000"} is not.
If you receive a JSON object, you need to convert it to JS object by
let result = JSON.parse(json)
and then
parseInt(result.dueAmount)
Try below code (Don't need to use JSON.stringify)
var userDueDate =res.Items[0].dueDate;
var userDueAmount = res.Items[0].dueAmount;
var userTotalBalance = res.Items[0].totalBalance;
var intUsingParseInt = parseInt(userDueAmount);
console.log('by using Parse : ' + intUsingParseInt + ' and the type is :' + (typeof intUsingParseInt));
Assuming that res is a JSON object. You can simply use parseInt function to get number format.
var am = parseInt(res.Items[0].dueAmount)
You should not use JSON.stringify here. Cause it converts a JSON object to a String.
Related
I have this JSON file.
Using rescript I want to :
Read the file.
Extract data from the file.
Write result in a new file.
{
"name": "name",
"examples": [
{
"input": [1,2],
"result": 1
},
{
"input": [3,4],
"result": 3
}
],
}
I was able to acheive this using JavaScript
var file = Fs.readFileSync("file.json", "utf8");
var data = JSON.parse(file);
var name = data.name
var examples = data.examples
for (let i = 0; i< examples.length; i++){
let example = examples[i]
let input = example.input
let result = example.result
let finalResult = `example ${name}, ${input[0]}, ${input[1]}, ${result} \n`
Fs.appendFileSync('result.txt',finalResult)
}
These are my attempts at writing it in Rescript and the issues I ran into.
let file = Node.Fs.readFileSync("file.json", #utf8)
let data = Js.Json.parseExn(file)
let name = data.name //this doesn't work. The record field name can't be found
So I have tried a different approach (which is a little bit limited because I am specifying the type of the data that I want to extract).
#module("fs")
external readFileSync: (
~name: string,
[#utf8],
) => string = "readFileSync"
type data = {name: string, examples: array<Js_dict.t<t>>}
#scope("JSON") #val
external parseIntoMyData: string => data = "parse"
let file = readFileSync(~name="file.json", #utf8)
let parsedData = parseIntoMyData(file)
let name = parsedData.name
let example = parsedData.examples[0]
let input = parsedData.examples[0].input //this wouldn't work
Also tried to use Node.Fs.appendFileSync(...) and I get The value appendFileSync can't be found in Node.Fs
Is there another way to accomplish this?
It's not clear to me why you're using Js.Dict.t<t> for your examples, and what the t in that type refers to. You certainly could use a Js.Dict.t here, and that might make sense if the shape of the data isn't static, but then you'd have to access the data using Js.Dict.get. Seems you want to use record field access instead, and if the data structure is static you can do so if you just define the types properly. From the example you give, it looks like these type definitions should accomplish what you want:
type example {
input: (int, int), // or array<int> if it's not always two elements
result: int,
}
type data = {
name: string,
examples: array<example>,
}
I have been trying to parse JSON, which have 3 different set of data where one element have various number of children and sometimes none. I am getting an error when there is no children present or only one present. I declared the JSON as var data.
JSON A
{
"floorplan": [
{
"title": "plan1",
"url": "https://media.plan1.pdf"
},
{
"title": "plan2",
"url": "https://media.plan2.pdf"
}
]
}
JSON B
{"floorplan": []}
JSON C
{
"floorplan": [
{
"title": "plan1",
"url": "https://media.plan1.pdf"
}
]
}
I parsed the JSON like this:
var items = JSON.parse(data);
return {
floorplan1: items.floorplan[0].url;
floorplan2: items.floorplan[1].url;
}
But, it only returned data for the JSON A, for other 2 it gave TypeError: Cannot read property 'url' of undefined.
I modified the code to check if floorplan have at least one child and then parse data.
var items = JSON.parse(data);
var plan = items.floorplan[0];
if(plan){
return {
floorplan1: items.floorplan[0].url;
floorplan2: items.floorplan[1].url;
}
}
The new code returned data for JSON A and B(as empty row), but gave error for C. C have one child still it got the error.
I also tried this code, still got the error for JSON C.
var items = JSON.parse(data);
var plan = items.floorplan[0];
var plan1;
var plan2;
if(plan){
plan1 = items.floorplan[0].url;
plan2 = items.floorplan[1].url;
}
return{
floorplan1 : plan1 ? plan1 : null;
floorplan2 : plan2 ? plan2 : null;
}
Is there any method I can try to get data returned for all 3 types of JSON?
let data = `
[{"floorplan": [{
"title": "plan1",
"url": "https://media.plan1.pdf"
}, {
"title": "plan2",
"url": "https://media.plan2.pdf"
}]},
{"floorplan": []},
{"floorplan": [{
"title": "plan1",
"url": "https://media.plan1.pdf"
}]}]`;
let json = JSON.parse(data);
//console.log(json);
json.forEach(items=>{
//console.log(items);
let o = {
floorplan1: items.floorplan.length > 0 ? items.floorplan[0].url : '',
floorplan2: items.floorplan.length > 1 ? items.floorplan[1].url : ''
};
console.log(o);
o = {
floorplan1: (items.floorplan[0] || {'url':''}).url,
floorplan2: (items.floorplan[1] || {'url':''}).url
};
console.log(o);
o = {
floorplan1: items.floorplan[0]?.url,
floorplan2: items.floorplan[1]?.url
};
console.log(o);
const {floorplan: [one = {url:''}, two = {url:''}]} = items;
o = {
floorplan1: one.url,
floorplan2: two.url
};
console.log(o);
});
Sure. A few ways, and more than I have here. I have put all the raw data into one string, parsed it into json and then iterated through that. In each loop my variable items will correspond to one of the json variables you created and referenced in your question as items.
In the first example, I check to make sure that items.floorplan has at least enough elements to contain the url I'm trying to reference, then use the ternary operator ? to output that URL if it exists or an empty string if it doesn't.
In the second example, I use the || (OR) operator to return the first object that evaluates to true. If items.floorplan[x] exists, then it will be that node, and if it doesn't I provide a default object with an empty url property on the right hand side, and then just use the url from the resulting object.
In the third, I use the optional chaining operator that was introduced in 2020. This method will return undefined if the url doesn't exist.
In the fourth example, I use destructuring to pull values out of the items variable, and make sure that there is a default value for url in case the items variable doesn't have a corresponding value.
But there are many more ways to go about it. These are just a few, and you can't necessarily say which approach is better. It's dependent on your intent and environment. With the exception of optional chaining (which shows undefined if the property doesn't exist), you can see these produce the same results.
DOCS for optional chaining: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining
DOCS for destructuring: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
An article on destructuring: https://javascript.info/destructuring-assignment
I am trying to extract a JSON response.When I try to access the object within the json array it returns undefined
weather= [{"id":711,"main":"Smoke","description":"smoke","icon":"50d"}]
var x=JSON.stringify(weather)
x[0].main= returns =>undefined
You can simply use Array#map OR Array#forEach function to get all you JSON data. You do not need to use JSON.stringify in your response.
Demo:
let weather = [{
"id": 711,
"main": "Smoke",
"description": "smoke",
"icon": "50d"
}]
weather.map(function(x) {
console.log(x.id) //711
console.log(x.main) //Smoke
console.log(x.description) //smoke
console.log(x.icon) //50d
})
I'm not sure what you're trying to accomplish or what you've tried, but here is how that works:
const weather = [{"id":711,"main":"Smoke","description":"smoke","icon":"50d"}]
document.querySelector('#id').textContent = weather[0].id
document.querySelector('#json').textContent = JSON.stringify(weather)
ID:
<div id="id"></div>
Stringified JSON:
<div id="json"></div>
To access an element of an array you can reference an index or loop through it:
const myArray = [1, 2, 3];
myArray[0] // 1
myArray[1] // 2
myArray[2] // 3
for (let i = 0 ; i < myArray.length ; i++) {
console.log(myArray[i]);
}
To access a property of an object you can either use dot notation or the key name as the index:
const myObject = {'a': 1, 'b': 2}
myObject.a // 1
myObject['b'] // 2
JSON.stringify converts your JSON into a string. This is useful for sending it over a connection to a host that may or may not recognize JSON.
Using Node js and Sequelize ORM, i'm getting a data set. I need to add a new attribute to received data and send it to client side. This is what i tried.
Code Block 1
var varAddOns = { "id" : 5, "Name" : "Cheese"};
global.meal.findOne(
{
where: { id: 5 }
}).then(varMeal => {
var obj = {};
obj = varMeal;
obj.addons = varAddOns;
res.send(obj);
});
It returns a json like below. (Actually it does not contain "addons" data)
Code Block 2
{
"id": 12,
"mealName": "Burger",
"description": "Oily food",
}
but actually what i want is,
Code Block 3
{
"id": 12,
"mealName": "Burger",
"description": "Oily food",
"addons" : {
"id" : 5,
"Name" : "Cheese"
}
}
I tried something like below and it also wont work. (It returns same json as "Code Block 2'.)
Code Block 4
var newJson = {};
newJson = JSON.stringify(varMeal);
newJson['addons'] = varAddOns;
var retVal = JSON.parse(newJson);
res.send(retVal);
Can you help me to figure out, where the issue is?
EDIT
Code Block 5
var newJson = {};
newJson = varMeal;
newJson['addons'] = varAddOn;
var retVal = newJson;// JSON.parse(newJson);
res.send(retVal);
I tried 'Code block 5' as well. Same result comes out as 'Code block 2'. When I use JSON.parse(newJson), it was thrown an error. (Error is Unexpected token o in JSON at position 1)
You need to call .get on your model instance, and then attach extra properties to it:
var varAddOns = { "id" : 5, "Name" : "Cheese"};
global.meal.findOne(
{
where: { id: 5 }
}).then(varMeal => {
var obj = {};
obj = varMeal.get();
obj.addons = varAddOns;
res.send(obj);
});
A few things:
When you call findOne, Sequelize return a model instance, not a plain JS object with your data.
If you want to add extra properties to send to your user, you will first need to convert your model instance to a JS object with your data. You can do this by calling varMeal.get(). From there, you can add extra properties to it.
There is no need to prepend your variables with "var". It would be better to simply name your variable meal
you need the JSON to be an object when you are declaring newJson['addons'] as a nested object
Have you tried (in code block 4) not stringifying varMeal?
I'm currently working with trying to extract bits of information from a complicated json based database. After NSJSONSerialization.JSONObjectWithData I get output like follows (some returns added for clarity)
[
"title": Recorder Suite In A Minor - Viola Concerto - Tafelmusik,
"estimated_weight": 85,
"year": 0,
"thumb": ,
"identifiers": <__NSArrayI 0x600000089970>(
{
description = Text;
type = Barcode;
value = 4891030501560;
},
{
description = Printed;
type = Barcode;
value = "4 891030 501560";
},
{
type = ASIN;
value = B0000013L9;
},
{
type = "Mould SID Code";
value = "ifpi 8412";
},
{
type = "Matrix / Runout";
value = "CD PLANT AB 8550156 CDM01";
},
{
description = "SPARS Code";
type = Other;
value = DDD;
},
{
type = "Label Code";
value = "LC 9158";
}
),
"id": 885370,
"date_changed": 2014-06-17T03:53:03-07:00,
"master_url": https://api.discogs.com/masters/495830,
etc … ]
In particular, I need to know how to get the information out of the nested array. Note that the array is not (obviously) a nested dictionary - given the equal signs and the repeated keys. Any help with how to parse this would be appreciated.
I would use a Pod like SwiftyJSON.
First, you need to install CocoaPods, and then go for SwiftyJSON.
I would parse nested arrays in the following manner:
let json = JSON(data: dataFromNetworking)
if let items = json["items"].array {
for item in items {
if let title = item["title"].string {
println(title)
}
}
}
Check out the documentation and Usage section of SwiftyJSON for more info.
Cheers...