I am working on an nodejs app which reads data from a json file. Now I want to edit this json file in js (write to it). How do I do this ?
Here is my js code: `
var fs = require("fs")
//function for file input
function getFile(filename) {
var data = fs.readFileSync(filename,"ascii")
return data }
//parsing json
var jsonString = [getFile("File.json")]
var jsonObj = JSON.parse(jsonString)`
Modify the jsonObj as you want, create a new object or whatever, then write the file:
fs.writeFileSync("File.json", jsonData);
This will overwrite the file if it exists, so that way you edit the file.
You can load a json file by requiring it.
var contents = require('/path/to/file.json');
Iterate contents just like a regular object.
A JSON object, when parsed is, like any other JS object. Use object dot notation to access any data you want.
For example a value:
console.log(isonObi.something.value)
For example a value in an array:
console.log(isonObi.something[0].value)
From eyp
Modify the jsonObj as you want, create a new object or whatever, then write the file:
fs.writeFileSync("File.json", jsonData);
This will overwrite the file if it exists, so that way you edit the file.
With nodeJS, you can require a JSON file.
Supposing you get this JSON file :
//test.json
[
{
"name": "toto",
"code": "4"
},
{
"name": "test",
"code": "5"
}
];
Then, you can require this file and perform some modification :
var json = require('./test.json');
json.forEach(function(elm){
elm.name = 'test';
});
I am using this script to retrive JSON data from a file to my page.
$.getJSON('json/data.json', function(data) {
$('#getJSON-results').html(JSON.stringify(data));
});
<div id="getJSON-results"></div>
Right now it jsut displays all the data from JSON file as a string on the page.
How would I take the data from my JSON file and place each array into a variable? My data in the JSON file looks like this:
[{"target": "summarize(first, \"1d\", \"sum\")", "datapoints": [[38.393148148148143, 1423958400], [90.800555555555633, 1424044800], [159.06037037037032, 1424131200], [245.5933333333335, 1424217600], [126.94796296296299, 1424304000], [120.37111111111113, 1424390400], [103.04148148148151, 1424476800], [99.273796296296368, 1424563200], [89.38203703703708, 1424649600], [92.970462962963012, 1424736000], [105.62666666666664, 1424822400], [110.33962962962967, 1424908800], [118.54981481481482, 1424995200], [100.08018518518523, 1425081600], [92.52277777777779, 1425168000], [98.647619047618974, 1425254400], [94.585000000000008, 1425340800], [85.568796296296284, 1425427200], [157.82222222222222, 1425513600], [109.7596296296296, 1425600000], [112.53324074074077, 1425686400], [89.392592592592649, 1425772800], [97.253518518518518, 1425859200], [73.424629629629635, 1425945600], [92.377592592592578, 1426032000], [76.117870370370397, 1426118400], [77.83953703703699, 1426204800], [66.643518518518533, 1426291200], [63.748055555555531, 1426377600], [137.30018518518517, 1426464000], [53.480648148148134, 1426550400]]},
{"target": "summarize(second, \"1d\", \"sum\")", "datapoints": [[2.7291600529100535, 1423958400], [5.7797089947089892, 1424044800], [3.4261574074074059, 1424131200], [5.0516335978835958, 1424217600], [6.2272420634920582, 1424304000], [11.752605820105822, 1424390400], [7.8688624338624269, 1424476800], [5.7305555555555525, 1424563200], [5.2784391534391499, 1424649600], [6.4652380952380897, 1424736000], [4.7690277777777741, 1424822400], [4.1451587301587258, 1424908800], [8.4178902116402039, 1424995200], [4.7948611111111061, 1425081600], [4.8153835978835939, 1425168000], [5.3873148148148111, 1425254400], [7.2819378306878262, 1425340800], [5.2084391534391488, 1425427200], [8.098492063492051, 1425513600], [5.6563822751322697, 1425600000], [5.3091468253968195, 1425686400], [4.7850396825396793, 1425772800], [3.8716931216931179, 1425859200], [3.1934325396825369, 1425945600], [3.2083531746031722, 1426032000], [3.3434391534391512, 1426118400], [3.6162235449735438, 1426204800], [3.2094179894179891, 1426291200], [2.3699537037037026, 1426377600], [4.3973544973544945, 1426464000], [2.1901388888888893, 1426550400]]},
{"target": "summarize(third, \"1d\", \"sum\")", "datapoints": [[5.3710185185185182, 1423958400], [11.25367724867724, 1424044800], [8.2990079365079268, 1424131200], [8.710694444444437, 1424217600], [9.6381216931216898, 1424304000], [9.3845105820105807, 1424390400], [9.7305820105820047, 1424476800], [8.6268055555555474, 1424563200], [10.589166666666673, 1424649600], [10.235462962962957, 1424736000], [10.455892857142853, 1424822400], [14.282407407407405, 1424908800], [17.774404761904758, 1424995200], [18.154120370370364, 1425081600], [16.249543650793651, 1425168000], [15.29764550264551, 1425254400], [16.267671957671972, 1425340800], [20.121488095238096, 1425427200], [27.007685185185196, 1425513600], [17.577962962962971, 1425600000], [17.020873015873018, 1425686400], [14.627685185185191, 1425772800], [15.824821428571433, 1425859200], [11.837579365079364, 1425945600], [13.292539682539683, 1426032000], [12.064074074074073, 1426118400], [12.279457671957676, 1426204800], [9.3799074074073978, 1426291200], [7.8777314814814732, 1426377600], [13.161825396825407, 1426464000], [7.2587499999999956, 1426550400]]}]
I am new to using JSON and would also appreciate any advice on the approach I'm taking.
How can I now make this data accsessable outside the getJSON?
$.getJSON('json/data.json', function(data) {
yourData = data;
makeMeGlobal = yourData[0];
});
console.log(makeMeGlobal.datapoints);
Changing your function to the following will result in an object you can then reference normally:
$.getJSON('json/data.json', function(data) {
yourData = data;
});
You could then get the first set of datapoints like this:
yourData.datapoints[0]
Should be:
data.forEach(function (obj) {
// obj now has each JSON object in this array
var test = obj.target;
}
When you get a JSON from AJAX, it's already ready for use in the browser. This is one of the nice perks of using JSON over XML.
It's already an array, because the original JSON string was parsed by jQuery. If you use stringify, you will get a string which contains the JSON representing the array (not useful for your purposes, as it's the same string returned by the server).
For example:
$.getJSON('json/data.json', function(data) {
// Here, data is already an array.
var data_length = data.length;
for (var i = 0; i < data_length; i++) {
var obj = data[i]; // Here we have an object from the array
alert("I have an object which target is " + obj.target);
}
});
You need to iterate through json to retrieve the value you need and append the html.More infor # https://stackoverflow.com/a/18238241/909535 Something like this
`$.getJSON('json/data.json', function(data){
data.forEach(
function(val, index, array) {
//val.target will have target attribute's value
//val.datapoints is a array which you can iterate
}
);
}
);`
How do you reference a JSON object in JavaScript?
I have a JSON response from a Rest web service and trying to reference the contents of the response which I have parsed to JSON by way JSON.Parse(response)
Sample JSON:
{
"HotelListResponse":{
"customerSessionId":"",
"numberOfRoomsRequested":1,
"moreResultsAvailable":true,
"cacheKey":"",
"cacheLocation":"",
"cachedSupplierResponse":{
"#supplierCacheTolerance":"NOT_SUPPORTED",
"#cachedTime":"0",
"#supplierRequestNum":"101",
"#supplierResponseNum":"",
"#supplierResponseTime":"",
"#candidatePreptime":"14",
"#otherOverheadTime":"",
"#tpidUsed":"",
"#matchedCurrency":"true",
"#matchedLocale":"true"
},
"HotelList":{
"#size":"20",
"#activePropertyCount":"101",
"HotelSummary":[
{
"name":"name1"
},
{
"name":"name2"
}
]
}
}
}
How can I, for example reference the customerSessionId? And the second HotelSummary name?
For customerSessionId I have tried jsonObject.customerSessionId which returns undefined. For the second hotel summary name I have tried jsobObject.HotelList.HotelSummary[1].name which is undefined too.
Given the JSON string above parsed and assigned to a variable as such:
var response = JSON.Parse(jsonString);
you should be able to access it like this:
var customerSessionId = response.HotelListResponse.customerSessionId;
Here's the working solution fiddle
As you can see, you need to reference HotelListResponse,
so if your var result holds your json object, then you can fetch the values by using
var first = result.HotelListResponse.customerSessionId
var second = result.HotelListResponse.HotelList.HotelSummary[1].name
I have a json arry
var students = {"apResults":[{"offid":"267","item_name":"","offer_name":"fsdfsf","stlongitude":"77.5945627","stlatitude":"12.9715987"},
{"offid":"265","item_name":"","offer_name":"vess offer shops","stlongitude":"","stlatitude":""},
{"offid":"264","item_name":"","offer_name":"vess ofer shop","stlongitude":"","stlatitude":""},
{"offid":"263","item_name":"","offer_name":"ofer frm vess","stlongitude":"77.5943760","stlatitude":"12.9716060"},
{"offid":"262","item_name":"","offer_name":"offer hungamma","stlongitude":"77.5943760","stlatitude":"12.9716060"},
{"offid":"261","item_name":"","offer_name":"offer hungamma","stlongitude":"77.5943760","stlatitude":"12.9716060"},
{"offid":"260","item_name":"","offer_name":"offer1","stlongitude":"77.5943760","stlatitude":"12.9716060"},
{"offid":"259","item_name":"","offer_name":"offer","stlongitude":"77.5943760","stlatitude":"12.9716060"}]}
How i can parse this json arry using json.parse. I have tried this code
for(i=0;i<students.apResults.length;i++)
{
var contact = JSON.parse(students.apResults);
var offid = contact.offid;
alert(offid)
}
But its giving an error JSON.parse: unexpected character.Edited my question
That's not a json string, that's a regular javascript variable:
for(i=0;i<students.Maths.length;i++)
{
var contact = students.Maths[i];
var fullname = contact.Name;
alert(fullname)
}
for(i=0;i<students.apResults.length;i++)
{
var contact = JSON.parse(students.apResults[i].offid);
alert(contact)
}
JSON parses strings, not objects/arrays.
why need parsing when you can access it like students.Maths[i].Name
students is not a JSON array, it's an actual array. You don't have to parse because it's not a string. So you can access directly to the data you need:
for(i=0;i<students.Maths.length;i++) {
var contact = students.Maths[i];
var fullname = contact.Name;
alert(fullname)
}
You can't parse students because is not a JSON. It's simple object.
However this will work:
var students = JSON.stringify(students); // if you want to send data
students = JSON.parse(students); // after receiving make a object from it
//use like any object
for(i=0;i<students.Maths.length;i++)
{
var contact = students.Maths[i];
var fullname = contact.Name;
alert(fullname)
}
Of course it doesn't make sense to write it that way unless you send students data to other site or program.
Edit:
You don't need JSON in this code at all. But if you want to test JSON.parse() do it this way:
var students = { ... } // your data
var students = JSON.stringify(students); // students is `object`, make it `string`
students = JSON.parse(students); // now you can parse it, `students` is object again
for(i=0;i<students.apResults.length;i++) {
var contact = students.apResults; // no JSON
var offid = contact.offid;
alert(offid)
}
That should work.
What you have is a javascript object. So, you won't need the JSON.parse
for(i=0;i<students.Maths.length;i++)
{
var contact = students.Maths[i]);
var fullname = contact.Name;
alert(fullname)
}
this should be ok
The idea of JSON is for the exchange of objects represented as a structured string (in a nutshell). What you've got there is simply an object. It's unnecessary (and impossible) to parse and object that isn't JSON into a javascript object; what you have is the outcome of what you would expect from a parsed JSON string.