Javascript - how to loop through dict inside a list - javascript

So I am pretty new when it comes to Javascript and it is as simple as read a json list with a value of:
{
"URL": [{
"https://testing.com/en/p/-12332423/": "999"
}, {
"https://testing.com/en/p/-123456/": "123"
},
{
"https://testing.com/en/p/-456436346/": "422"
}
]
}
What I would like to do is to have both the URL and the amount of numbers etc
"https://testing.com/en/p/-12332423/" and "999"
and I would like to for loop so it runs each "site" one by one so the first loop should be
"https://testing.com/en/p/-12332423/" and "999"
second loop should be:
"https://testing.com/en/p/-123456/" and "123"
and so on depending on whats inside the json basically.
So my question is how am I able to loop it so I can use those values for each loop?

As Adam Orlov pointed out in the coment, Object.entries() can be very useful here.
const URLobj = {
"URL": [{
"https://testing.com/en/p/-12332423/": "999"
}, {
"https://testing.com/en/p/-123456/": "123"
},
{
"https://testing.com/en/p/-456436346/": "422"
}
]
};
URLobj.URL.forEach(ob => {
console.log('ob', ob);
const entries = Object.entries(ob)[0]; // 0 just means the first key-value pair, but because each object has only one we can just use the first one
const url = entries[0];
const number = entries[1];
console.log('url', url);
console.log('number', number);
})

You mean something like this using Object.entries
const data = {
"URL": [
{"https://testing.com/en/p/-12332423/": "999"},
{"https://testing.com/en/p/-123456/": "123"},
{"https://testing.com/en/p/-456436346/": "422"}
]
}
data.URL.forEach(obj => { // loop
const [url, num] = Object.entries(obj)[0]; // grab the key and value from each entry - note the [0]
console.log("Url",url,"Number", num); // do something with them
})

let's call your object o1 for simplicity. So you can really go to town with this link - https://zellwk.com/blog/looping-through-js-objects/
or you can just use this code :
for(var i = 0; i < o1.URL.length; i++) {
//each entry
var site = Object.keys(URL[i]) [0];
var value = Object.values(URL[i]) [0];
// ... do whatever
}
don't forget each member of the array is an object (key : value) in its own right

You can extract the keys and their values into another object array using map
Then use the for loop on the newly created array. You can use this method on any object to separate their keys and values into another object array.
const data = {
"URL": [{
"https://testing.com/en/p/-12332423/": "999"
}, {
"https://testing.com/en/p/-123456/": "123"
},
{
"https://testing.com/en/p/-456436346/": "422"
}
]
}
var extracted = data.URL.map(e => ({
url: Object.keys(e)[0],
number: Object.values(e)[0]
}))
extracted.forEach((e) => console.log(e))

Related

how to remove key values in array of objects

I am having a array of objects which looks like this
var data = [
{
"id": "K014-s1",
"status": true,
"amount": 992,
"check": true,
},
{
"id": "K014-s2",
"status": false,
"amount": 10992,
"check": true,
}
]
I want only certain key values from the object in the array
Required Output:
var data = [
{
"id": "K014-s1",
"amount": 992,
},
{
"id": "K014-s2",
"amount": 10992,
}
]
Code I tried:
var filteredData = []
var result = data.map((obj) => {
filteredData.push(obj.id)
})
console.log(filteredData)
I tried. But don't Know how to make it. Please Help me with some solutions
instead of pushing object to another array,you can simply map your data like this
var result = data.map((obj) => {
return {
id:obj.id,
amount:obj.amount
}
})
Array.prototype.map already creates a new array, so result will already be the new value you are looking for.
The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.
var filteredResult = data.map((obj) => {
//additional logic, if needed here.
return {
id: obj.id,
amount: ob.amount,
}
})
Alternatively you can of course use a for loop or array.prototype.forEach to achieve the same:
var filteredData = []
data.forEach((obj) => {
filteredData.push({
id: obj.id,
amount: ob.amount,
})
})
No need to initiate a new array because the map method returns a new array what you can do is map the array then delete the property or method that you want then return the new array. Here's a simple solution that you use for your reference
const filteredData = data.map(newData => {
delete newData.status
delete newData.check
return newData
})
Simply you can loop over array using forEach method and delete key, value pairs. For example data.forEach((obj) => { delete obj.status; delete obj.check; }) since array is a reference type you can easily mutate it and not create a duplicate of data.

Create new object with unique elements from objects of array of objects

I have an Array of Objects. Every object in this Array has some Keypairs. One of this Keypairs ("obj", for example) is an Array of Objects too.
Example what I have:
const arrOfObj = [
{
"id": 1
"obj": {
"arr1": ["arr1-1"],
"arr2": ["arr2-1", "arr2-2"],
"arr3": ["arr3-1", "arr3-2"]
}
},
{
"id": 1
"obj": {
"arr1": ["arr1-2"],
"arr2": ["arr2-1", "arr2-3"],
"arr3": ["arr3-1", "arr3-3"],
"arr4": ["arr4-1"],
}
},
];
I need to get new Object of "obj" Objects with unique keys and unique elements inside them.
Example what I need:
const newObj = {
"arr1": ["arr1-1", "arr1-2"],
"arr2": ["arr2-1", "arr2-2", "arr2-3"],
"arr3": ["arr3-1", "arr3-2", "arr3-3"],
"arr4": ["arr4-1"],
}
All of this comes dynamically from API by request, so I don`t know the names of this keypairs, but i need to store them.
I have Solution, but I`m new in JavaScript, and want to know how to simplify and improve my poor Code.
1. First, I`m defining the new Object and retrieving the Names for his keypairs from "arrOfObj".
let filterObj = {};
arrOfObj.forEach(function (item) {
for (let key in item.obj) {
filterObj[key] = [];
}
});
2. After that I`m getting all the Elements of every Array from "arrOfObj" and store them in new Object "filterObj" in the Keypair with the same Name.
arrOfObj.forEach(function (item) {
for (let key in item.obj) {
for (let element = 0; element < item.obj[key].length; element++) {
filterObj[key].push(item.obj[key][element]);
}
}
});
3. To the end I`m filtering Arrays to get unique Elements only.
for (let key in filterObj) {
filterObj[key] = Array.from(new Set(filterObj[key]));
}
It works, I`ve got what I want, but it seems to much monstrously. How this code can be simplified the best way?
Thanks for the help and advices.
You can use some destructuring and Object.entries() and Object.keys() to streamline this and do everything to the new Object only
const newObj = {}
arrOfObj.forEach(({obj}) => {
Object.entries(obj).forEach(([k, arr]) => {
newObj[k] = newObj[k] || [];
newObj[k].push(...arr);
})
});
Object.keys(newObj).forEach(k => newObj[k] = [...new Set(newObj[k])]);
console.log(newObj)
<script>
const arrOfObj=[{id:1,obj:{arr1:["arr1-1"],arr2:["arr2-1","arr2-2"],arr3:["arr3-1","arr3-2"]}},{id:1,obj:{arr1:["arr1-2"],arr2:["arr2-1","arr2-3"],arr3:["arr3-1","arr3-3"],arr4:["arr4-1"]}}];
</script>
Another solution using Object#fromEntries, Array#reduce, Object#entries, Array#forEach, Set, and Map:
const arrOfObj = [ { "id": 1, "obj": { "arr1": ["arr1-1"], "arr2": ["arr2-1", "arr2-2"], "arr3": ["arr3-1", "arr3-2"] } }, { "id": 1, "obj": { "arr1": ["arr1-2"], "arr2": ["arr2-1", "arr2-3"], "arr3": ["arr3-1", "arr3-3"], "arr4": ["arr4-1"] } } ];
const filterObj =
// transform the resulting list of key-values pairs to an object at the end
Object.fromEntries(
// get a map of array name as key and its unique items as value
[...arrOfObj.reduce((map, { obj = {} }) => {
// iterate over current element's object to update the map
Object.entries(obj).forEach(([currentKey, currentValues]) => {
const keyValues = [...(map.get(currentKey) || []), ...currentValues];
map.set(currentKey, [...new Set(keyValues)]);
});
return map;
}, new Map)]
);
console.log(filterObj);

Deleting json value with javascript

I have tried to many ways , but i am stuck with a simple function in javascript, and i don't know where i need to looking for ... the problem is this:
I have a Json file like this one:
{
"blacklist": [
{
"email": "strangemail#gmail.com"
},
{
"email": "strangemail1#gmail.com"
},
{
"email": "strangemail2#gmail.com"
},
{
"email": "fianlt#gmail.com"
},
{
"email": "finalstatustest#gmail.com"
}
]
}
I would like simple remove an email with a simple function like this one:
function cancel(email) // parameter that contain the value to delete
{
let rawdata = fs.readFileSync('pvt.json'); //get local json file
let mydata = JSON.parse(rawdata); //parsing rawdata
var key = email; //setting up key
delete mydata.blacklist[key]; //using delete function for delete an element
let data = JSON.stringify(mydata, null, 2); //stringify the result
fs.writeFileSync('pvt.json', data); // overwrite local file with new one with all changes
}
the problem is ... it doesn't works ... i don't know why ... i tried to read the documentation, but i didn't found any solution 😢
The delete operator is for removing a property from an object, using the property's name. You're trying to remove an entry from an array, using the value of a property of an object in the array.
Assuming email is a variable containing the email address in the entry you want to remove, filter is one easy way to do that:
mydata.blacklist = mydata.blacklist.filter(entry => entry.email !== email);
filter builds a new array from the entries in the original array that meet the criteria in the callback — in this case, that their email property doesn't match the email address you want to remove.
If you wanted to modify the array in place rather than creating a new one, you'd use findIndex and splice:
const index = mydata.blacklist.findIndex(entry => entry.email === email);
if (index !== -1) {
mydata.blacklist.splice(index, 1); // Remove the entry at the index
}
Delete works to delete a key-value from an object. Here you have an array of items[objects]. You should use filter to remove unwanted element.
Update:
function cancel(selectedEmail) {
let rawdata = fs.readFileSync("pvt.json"); //get local json file
let mydata = JSON.parse(rawdata); //parsing rawdata
mydata.blacklist = mydata.blacklist.filter(
(item) => item.email !== selectedEmail.email
);
fs.writeFileSync("pvt.json", JSON.stringify(mydata, null, 2)); // overwrite local file with new one with all changes
}
Sample:
const info = {
blacklist: [
{
email: "strangemail#gmail.com",
},
{
email: "strangemail1#gmail.com",
},
{
email: "strangemail2#gmail.com",
},
{
email: "fianlt#gmail.com",
},
{
email: "finalstatustest#gmail.com",
},
],
};
const selectedEmail = {email: "finalstatustest#gmail.com"}
info.blacklist = info.blacklist.filter(item => item.email !== selectedEmail.email)
console.log(info)

remove object from array if property value match

I have array of objects that look like:
{
"brandid": id,
"brand": string,
"id": id,
"categoryId": id,
"category": string,
"factory": string,
"series": string,
"status": 0,
"subStatus": 1
}
if the series property value matches another series property value in the other objects in the array, that object needs to be removed from the array.
Currently I have attempted to push them to a duplicate Array with :
const seriesResCopy = seriesRes;
const dupArray = []
for (const thing of seriesResCopy) {
for (const item of seriesRes) {
if (thing.series === item.series) {
dupArray.push(item);
}
}
}
but this does not work. From examples I have seem my issue has been that I do not have a definite list of duplicate values to look for.
Any help would be much appreciated.
You could use a Set of series to filter out duplicates:
const exists = new Set();
seriesRes = seriesRes.filter(({series}) => !exists.has(series) && exists.add(series));
This uses: Array.prototype.filter, Object destructuring and some logical tricks.
The same can be done by mutating the array:
const exists = new Set();
for(const [index, {series}] of seriesRes.entries()) {
if(!exists.has(series) {
exists.add(series);
} else {
seriesRes.splice(index, 1);
}
}
To filter duplicates from the array and keep the first instance:
let seriesWithoutDuplicates = seriesRes.filter((s, i, self) => {
return self.findIndex(z => z.series === s.series) === i;
});

how to get multiple keys from nested JSON in javascript?

My JSON is like:
{
"boundaries": [
{
"boundary": {
"boundaryId": "45083021141",
"boundaryType": "USA_POSTCODE",
"boundaryRef": "B1"
}
}
],
"themes": [
{
"TheftCrimeTheme": {
"boundaryRef": "B1",
"individualValueVariable": [
{
"name": "2013 Theft Crime",
"description": "Theft Crime for 2013",
"count": 2080
}
]
}
},
{
"BurglaryCrimeTheme": {
"boundaryRef": "B1",
"individualValueVariable": [
{
"name": "2013 Burglary Crime",
"description": "Burglary Crime for 2013",
"count": 302
}
]
}
}
]
}
I want to get value of count to display in graph. As you can see in the above json, inside themes there are two keys i.e TheftCrimeTheme and BurglaryCrimeTheme. I want to get value of count in everycrimetheme. For this I did the below code:
$http.get("http://152.144.218.70:8080/USACrime/api/crimeAPI?city="+$scope.strCity+"&crimeType="+$scope.type1+"&years="+$scope.type+"&month="+$scope.type2).success(function (result) {
for(var i=0;i<result.themes.length;i++){
var crime={};
console.log("did",result.themes[i]);
var test2 = result.themes[i];
console.log("test2",test2);
var test = test2[Object.keys(test2)];
console.log("test",test);
crime.name = Object.keys(result.themes[i]);
console.log("CrimeName",crime.name);
crime.data = [];
var test1 = test.individualValueVariable[0].count;
console.log("test1",test1);
crime.data.push(test1);
crime_data.push(crime);
}
});
My agenda is to plot graph showing count of every year.To achieve this firstly I have to get multiple keys like TheftCrimeTheme, BurglaryCrimeTheme etc. Then after that i can access value of count in individualValueVariable.
when I used Object.keys() method , I got an error "undefined" when i console values of nameR. Please suggest me how should i do this?
This function recieves info (as the whole json), and theme as the theme which you want to get the count (ie.: "BurglaryCrimeTheme").
getThemeCrimesCount = (info, theme) => {
const record = info.themes.find(obj => Object.keys(obj)[0] == theme)[theme];
return record.individualValueVariable.reduce((a, b) => a += b.count, 0);
}
getThemeCrimesCount(info, "BurglaryCrimeTheme"); // 302
getThemeCrimesCount(info, "TheftCrimeTheme"); // 2080
Formatting this to separate the elements for clarity.
// Builds and returns URL with query string attached.
const buildURL = (uri, params) => {
let queryParams = Object.keys(params).map(function(k) {
return encodeURIComponent(k) + '=' + encodeURIComponent(params[k])
}).join('&');
return uri + '?' + queryParams;
};
// Parses returned JSON object.
const parseStatistics = (result) => {
// My assumption here is that you are receiving a JSON string, which
// would need to be parsed into an object before being used.
let result = JSON.parse(result);
// Set base object
let namR = {};
// Iterate through themes array.
result.themes.forEach(function(element) {
// Find the object name for current theme.
let type = Object.keys(element)[0];
// Find count for current theme.
let count = element[type].individualValueVariable.count;
// Set count.
namR[type] = count;
});
// Log object
console.log(namR);
};
// Set up url info.
let params = {
city: $scope.strCity,
crimeType: $scope.type1,
years: $scope.type,
month: $scope.type2
};
let baseURL = "http://152.144.218.70:8080/USACrime/api/crimeAPI";
// Execute request.
$http.get(buildURL(baseURL, params)).success(parseStatistics(response));

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