Recursively create strings from objects - javascript

Hello I have json file:
var jsonData = {
"name": "James",
"age": 22,
"nodes": [
{
"name": "John",
"age": 24,
"nodes": [
{
"name": "Jack",
"age": 65,
"nodes": [
{
"name": "Harry",
"age": 70,
"nodes": []
}
]
},
{
"name": "Joe",
"age": 10,
"nodes": []
}
]
},
{
"name": "Daniel",
"age": 30,
"nodes": []
}
]
}
I need a function that returns output like this:
James 22
James - John 24
James - John - Jack 65
James - John - Jack - Harry 70
James - John - Joe 10
James - Daniel 30
I tried to use recursive function but I don't know how to return output like this one and return age only on last child..
Code:
var json = jsonData;
var prev = [];
function sortData(obj, prev) {
var i = 0;
prev.push(obj.name + " " + obj.age);
console.log(prev);
if (obj.nodes.length > 0) {
while (i < obj.nodes.length) {
sortData(obj.nodes[i], prev);
i++;
prev.pop();
}
}
}
sortData(json, prev);
My function returns output in multiple arrays, so I don't know how to operate with that to return output like that. Will be grateful for any help. Thanks!

You might consider just passing around strings representing the current property path recursively, that way you can just concatenate and pass the value around without worrying about it being mutated. Also, it'll be a lot easier to use array methods like forEach than to use an i variable and manually iterate:
var jsonData={"name":"James","age":22,"nodes":[{"name":"John","age":24,"nodes":[{"name":"Jack","age":65,"nodes":[{"name":"Harry","age":70,"nodes":[]}]},{"name":"Joe","age":10,"nodes":[]}]},{"name":"Daniel","age":30,"nodes":[]}]}
function getAge({ name, age, nodes }, oldPropStr = '') {
const propStr = (oldPropStr ? oldPropStr + ' - ' : '') + name;
console.log(propStr + ' ' + age);
nodes.forEach(node => getAge(node, propStr));
}
getAge(jsonData);
Also, you might note that the current variable name of jsonData is misleading. There's no such thing as a "JSON Object". If you have an object or array, then you have an object or array, full stop. JSON format is a method of representing an object in a string, like const myJSON = '{"foo":"bar"}'. If there are no strings, serialization, or deserialization involved, then JSON is not involved either. Maybe call the variable people or something instead?

Related

How to parse/filter data from JSON file in Javascript

Is there any way to parse/filter the data present in JSON file in a Javascript file.
Basically, I am calling JSON file into my local javascript. I am having trouble in reading specific data and printing.
Can anyone please help.
JSON file contains:
{
"Data": [
{
"name": "John",
"age": 30
},
{
"joined on":"Jan 2015",
"working on": "Automation",
}
]
}
I am trying to read the above JSON file as:
var jfile = require("./Example.json");
var test = JSON.parse(JSON.stringify(jfile))
console.log(test)
I get the output like this:
{ Data:
[ { name: 'John', age: 30 },
{ 'joined on': 'Jan 2015', 'working on': 'Automation' } ] }
From the above, I am interested in accessing/filtering out only one i.e. "name". I would like to print only the value "John" to the console.
I have tried to use the ".filter" method to the JSON.parse method but it throws me an error as:
JSON.parse(...).filter is not a function
Is there any way to perform this activity?
You can access it using . dot notation
var a = {
"Data": [{
"name": "John",
"age": 30
},
{
"joined on": "Jan 2015",
"working on": "Automation",
}
]
}
console.log(a.Data[0].name)
filter is an array method.
JSON.parse(...) will not give you an array. It will give you an object with a Data property. The value of that property is an array.
JSON.parse(...).Data.filter.
You can't just ignore parts of your data structure.
If you have multiple items in your array of different shapes, you can use this
Access the Data key with json.Data
map your array to transform its items into names
apply filter(Boolean) to take out those who are undefined
In your case you'll end up with an array containing only one name John
const getName = json => json.Data.map(x => x.name).filter(Boolean);
const json = {
"Data": [{
"name": "John",
"age": 30
},
{
"joined on": "Jan 2015",
"working on": "Automation",
}
]
};
console.log(getName(json));
Your JSON's main level is an object (not an array) and only arrays have .filter method.
So filter the array under Data key:
var test = JSON.parse(JSON.stringify(jfile)).Data.filter(/*something*/);
But better if you aren't re-parse JSON:
var test = jfile.Data.filter(/*something*/);
As Quentin mentioned in his comment, What is the use of below statement ?
var test = JSON.parse(JSON.stringify(jfile))
You can directly access the name property from the response.
Try this :
var obj = {
"Data": [{
"name": "John",
"age": 30
},
{
"joined on": "Jan 2015",
"working on": "Automation"
}
]
};
// Solution 1
console.log(obj.Data.map(item => item.name).filter(Boolean));
// Solution 2
console.log(obj.Data.filter(item => item.name).map(elem => elem.name));

How to create a new json out of three jsons?

I have 3 different jsons, I need to extrapolate some data from each and create a new json with it. The three jsons have an id identifier in common, a unique identifier, so We could use that as a match since they are actually three different big jsons.
On json one we have "id":"265", on two and three "article_id":"265", so these can be the reference point when we loop.
I never worked with json this way so I wouldn't know how to approach it. I have put jQuery and JS as tags as they're what I know best.
1
{
"id":"265",
"title":"Battle of Gettysburg",
"page_id":"4849",
"language_id":"en",
"original_time":"July 1\u20133, 1863"
}
2
{
"id":"185",
"original_name":"United States",
"country_id":"24",
"article_id":"265"
}
3
{
"id":"73",
"month":"July",
"year":"1863",
"suffix":"",
"article_id":"265"
}
So the end result I am looking for is a single json exactly like this, we take id and title as objects from json 1, then we grab original_name from json two and year object from json three and we'll have:
{
"id":"265",
"title":"Battle of Gettysburg",
"original_name":"United States",
"year":"1863"
}
NOTE
The json above are just examples, in reality they are three huge lists, what I could do (manually), is to join them in order to have a single json.
There is some terminology confusion here; based on your comments you could be asking one of two very different questions. Fortunately one of them is very simple to answer so let's do both.
(I am handwaving past the details of loading json strings into the browser and converting them into javascript objects.)
If you have three objects
...then this is just a matter of plucking out the fields you need individually when constructing an output object:
var in1 = {
"id": "265",
"title": "Battle of Gettysburg",
"page_id": "4849",
"language_id": "en",
"original_time": "July 1\u20133, 1863"
};
var in2 = {
"id": "185",
"original_name": "United States",
"country_id": "24",
"article_id": "265"
}
var in3 = {
"id": "73",
"month": "July",
"year": "1863",
"suffix": "",
"article_id": "265"
}
// construct a new object using the selected fields
// from each object in1, in2, or in3:
var out = {
id: in1.id,
title: in1.title,
original_name: in2.original_name,
year: in3.year
}
console.log(out);
If you have three lists of objects:
...in this case it's a lot more complicated (and a lot more interesting). In this case you would need to match fields from the objects in each list which share the same IDs.
The following is definitely not the most efficient or memory-conserving way to do this; I've spread things out to (hopefully) make it easier to follow what it's doing.
I'm making two assumptions:
within each list, all IDs are unique (meaning you won't have two objects with the same ID in one JSON file)
Every ID will appear in all three lists (meaning you don't need to handle missing fields in output)
/* Again handwaving past loading JSON strings and parsing
them into javascript objects, we'll just start with
three arrays: */
var input1 = [{
"id": "265",
"title": "Battle of Gettysburg",
"page_id": "4849",
"language_id": "en",
"original_time": "July 1\u20133, 1863"
},
{
"id": "1",
"title": "Foo",
"page_id": "123",
"language_id": "en",
"original_time": "July 1\u20133, 1863"
}
];
var input2 = [{
"id": "1",
"original_name": "Bar",
"country_id": "24",
"article_id": "265"
},
{
"id": "265",
"original_name": "United States",
"country_id": "24",
"article_id": "265"
}
]
var input3 = [{
"id": "1",
"month": "July",
"year": "Baz",
"suffix": "",
"article_id": "265"
},
{
"id": "265",
"month": "July",
"year": "1863",
"suffix": "",
"article_id": "265"
}
]
/* It would be much easier to find corresponding IDs
across these arrays if they weren't arrays. We'll
start by converting them into objects keyed by the
item ids: */
var convertArray = function(arr) {
var output = {};
arr.forEach(function(o) {
output[o.id] = o;
});
return output;
}
var obj1 = convertArray(input1);
var obj2 = convertArray(input2);
var obj3 = convertArray(input3);
/* Now if we need to find (say) the object with id "foo", we don't
need to search the whole array, but can just use `obj1["foo"]` or
`obj1.foo`.
The last step is to iterate over the list of IDs and repeatedly
do basically the same thing as in the "if you have three objects"
part above. The only difference is that we need to access the
object with the same ID in each of the input lists: */
var constructOutput = function(in1, in2, in3) {
var output = []; // we'll be outputting a list of objects again.
// step through every ID (assuming in1 contains all of them):
Object.keys(in1).forEach(function(id) {
var obj = {
id: id,
title: in1[id].title,
original_name: in2[id].original_name,
year: in3[id].year
}
output.push(obj);
});
return output;
}
var final = constructOutput(obj1, obj2, obj3)
console.log(final)
Essentially what you have to do is mimic a SQL JOIN using JavaScript objects:
Use JSON.parse() on all three JSON collections to turn them into arrays of objects.
Iterate through JSON 1 objects; for each object...
Iterate through JSON 2 objects, testing if article ID matches the ID from JSON 1 that we are iterating over. Save this object.
Iterate through JSON 3 objects, testing if ID matches the ID of the object we found from JSON 2. Save this object.
After you have all three objects, make a new object literal that contains only the fields you want:
{
Id: obj1.id,
Title: obj1.title,
Original_name: obj2.original_name,
Year: obj3.year
}
Should you want to combine n number of JSON objects, e.g. a list of objects you can take a functional approach and utilise reduce + filter.
const data = [{
"id":"265",
"title":"Battle of Gettysburg",
"page_id":"4849",
"language_id":"en",
"original_time":"July 1\u20133, 1863"
},
{
"id":"185",
"original_name":"United States",
"country_id":"24",
"article_id":"265"
},
{
"id":"73",
"month":"July",
"year":"1863",
"suffix":"",
"article_id":"265"
}];
const final = data.reduce((accu, { id, title }, index, array) => {
// Find any related objects
const matches = array.filter(data => data.article_id === id);
if (matches.length) {
// Flatten them for ease of access. Duplicate keys will override.
const flat = matches.reduce((arr, item) => ({ ...arr, ...item }), [])
// Return new object
return accu.concat({
...flat,
id,
title,
});
}
return accu;
}, []);
console.log(final, '<<')
// Witness
document.getElementById('results').innerHTML = JSON.stringify(final);
<div id="results" style="font-family: Courier; font-size 14px; color: #fff; background: #000; padding: 20px; max-width: 80vw;"></div>
Edited*
Maybe this is what you need?
let arrPages = [{
"id":"265",
"title":"Battle of Gettysburg",
"page_id":"4849",
"language_id":"en",
"original_time":"July 1\u20133, 1863"
}];
let arrArticles = [{
"id":"185",
"original_name":"United States",
"country_id":"24",
"article_id":"265"
},
{
"id":"73",
"month":"July",
"year":"1863",
"suffix":"",
"article_id":"265"
}];
let getResult = (arrInput, arrCompare) => {
let joinedItems = [];
arrInput.forEach(item => {
let newItem = { id: item.id, title: item.title };
arrCompare.forEach(subItem => {
if(subItem.article_id !== undefined && subItem.article_id === item.id){
if(subItem.original_name !== undefined)
newItem.original_name = subItem.original_name;
if(subItem.year !== undefined)
newItem.year = subItem.year;
}
});
joinedItems.push(newItem);
});
return joinedItems;
};
let result = getResult(arrPages, arrArticles);
console.log(result);
In the first part of the code i create a var that has the json data.
To solve the problema i create 2 functions, the order of the creation dosen't metter, the first function getJSONData() take the json data as parameter and return a object filtered by the keys defined in the array keys. The secound function just check if the current key is present in the array of keys, this function could be replaced by the jQuery.inArray() method.
// JSON data
var json = [{
"id":"265",
"title":"Battle of Gettysburg",
"page_id":"4849",
"language_id":"en",
"original_time":"July 1\u20133, 1863"
},
{
"id":"185",
"original_name":"United States",
"country_id":"24",
"article_id":"265"
},
{
"id":"73",
"month":"July",
"year":"1863",
"suffix":"",
"article_id":"265"
}]
// keys that i want
var keys = ["title", "original_name", "year"];
// var that will have the filtered data
var newJSON = getJSONData(json);
console.log(JSON.stringify(newJSON))
// this is the main function of the code
// here we iterate in the json creating a new object that has all the tags definid in the keys array
function getJSONData(arrayJSON){
var JSONFiltered = {};
for(var i in arrayJSON){
for(var key in arrayJSON[i]){
if(hasElement(key)){
JSONFiltered[key] = arrayJSON[i][key];
}
}
}
return JSONFiltered;
}
// this function is used to check a key is present in the array of keys
function hasElement(key){
for(var elem in keys){
if(keys[elem] == key) return true;
}
return false;
}

Get specific values form JSON Table with javascript over IDs

I have the following problem:
I have a JSON table with the data I need (found this on the internet since it is nearly what I need)
var testext ={"key1":[
{
"firstName":"Ray",
"lastName":"Villalobos",
"joined":2012
},
{
"firstName":"John",
"lastName":"Jones",
"joined":2010
}
]}
document.getElementById("demo").innerHTML=testext.key1[0].firstName;
This works fine but as you can see I still need an index [0] to get to the dataset I need.
I need to to this without this index...
like this here:
var testext = {
"key1": ["string1/1", "string1/2" ],
"key2": ["string2/1", "strin2/2"]
};
document.getElementById("demo").innerHTML = testext['key1'][0];
just combined so my variable would be something like :
document.getElementById("demo").innerHTML = testext['key1'].['firstname'];
Anyone an idea on how I can do this?
Thanks in advance.
You are almost correct. Restructure your array into an associative array of associative arrays. You can call them by array_name['first_index']['second_index'].
var testext = {
"key1": {
"firstName": "Ray",
"lastName": "Villalobos",
"joined": 2012
},
"key2": {
"firstName": "John",
"lastName": "Jones",
"joined": 2010
}
};
document.getElementById("demo").innerHTML = testext['key1']['firstName'];
<div id="demo">Default</div>

Accessing JSON array's through object properites

Let's say I have the next JSON file:
{
"shows": [
{
"name": "House of cards",
"rating": 8
},
{
"name": "Breaking bad",
"rating": 10
}
]
}
I want to access the rating of a show, by it's name. Something like this:
var rating = data.shows["House of cards"].rating;
Is this possible? Or something similar?
Thanks a lot!
You won't have such hash-style access just by deserializing that JSON sample.
Maybe you might be able to re-formulate how the data is serialized into JSON and use object literals even for shows:
{
"shows": {
"House of cards": {
"rating": 8
}
}
}
And you can still obtain an array of show keys using Object.keys(...):
Object.keys(x.shows);
Or you can even change the structure once you deserialize that JSON:
var x = { shows: {} };
for(var index in some.shows) {
x.shows[some.shows[index].name] = { rating: some.shows[index].rating };
}
// Accessing a show
var rating = x.shows["House of cards"].rating;
I suggest you that it should be better to do this conversion and gain the benefit of accessing your shows using plain JavaScript, rather than having to iterate the whole show array to find one.
When you use object literals, you're accessing properties like a dictionary/hash table, which makes no use of any search function behind the scenes.
Update
OP has concerns about how to iterate shows once it's an associative array/object instead of regular array:
Object.keys(shows).forEach(function(showTitle) {
// Do stuff here for each iteration
});
Or...
for(var showTitle in shows) {
// Do stuff here for each iteration
}
Update 2
Here's a working sample on jsFiddle: http://jsfiddle.net/dst4U/
Try
var rating = {
"shows": [
{
"name": "House of cards",
"rating": 8
},
{
"name": "Breaking bad",
"rating": 10
}
]
};
rating.shows.forEach(findsearchkey);
function findsearchkey(element, index, array) {
if( element.name == 'House of cards' ) {
console.log( array[index].rating );
}
}
Fiddle
var data = {"shows": [{"name": "House of cards","rating": 8},{"name": "Breaking bad","rating": 10}]};
var shows = data.shows;
var showOfRatingToBeFound = "House of cards";
for(var a in shows){
if(shows[a].name == showOfRatingToBeFound){
alert("Rating Of "+ showOfRatingToBeFound+ " is " +shows[a].rating);
}
}

How to parse through a JSON object Map

If I have a JSON Object Map :
var dataItem=[{
"Lucy":{
"id": 456,
"full_name": "GOOBER, ANGELA",
"user_id": "2733245678",
"stin": "2733212346"
},
"Myra":{
"id": 123,
"full_name": "BOB, STEVE",
"user_id": "abc213",
"stin": "9040923411"
}
}]
I want to iterate through this list and access the names (i.e. Lucy, Myra ) and corresponding information
All the loops that I came across looped through the list like this :
var dataItem = [
{"Name":"Nthal","Class":3,"SubjectName":"English "},
{"Name":"Mishal","Class":4,"SubjectName":"Grammer"},
{"Name":"Sanjeev","Class":3,"SubjectName":"Social"},
{"Name":"Michal","Class":5,"SubjectName":"Gk"},
]
for(x in dataItem)
{
alert(dataItem[x].Name);
alert(dataItem[x].Class);
alert(dataItem[x].SubjectName);
}
Thanks in advance
What you have there is not JSON, maybe because you've already parsed it. You have is an array consisting of a single object, with names for its keys. Regardless, I'll show you how to access that data:
var data = dataItem[0];
for(name in data) {
alert(name);
alert(data[name].id);
alert(data[name].full_name);
}
for (var x in dataItem[0]) {
if (dataItem[0].hasOwnProperty(x)) {
console.log(x);
}
}
http://jsfiddle.net/B44LW/
If you want other properties, then you can use the bracket notation:
dataItem[0][x].id

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