Find key in json array javascript

For a JSON, it makes traversing you don't need to make loop inside loopextracting data and manipulating it very simple. Thanks to jQuery foundation. A simple example. To get value associated with key "name" from a JSON stored in a variable "jsonObj" we need to write as simple as. There are lot of things you can do to contribute and support plugin.

How To Convert Javascript Array, Object To JSON using JSON.stringify() Method with Examples

The first thing you can do is use jsonQ, make your site awesome, spread the word and let me know you are using it. If you feel you can improve the plugin, fork the repositoryupdate the code and send me a pull request.

Spread the word and share it to your network. This plugin is developed and maintained by me Sudhanshu Yadav ignitersworld. If you have any query you can contact me at sudhanshuyadav2 gmail. Fork me on GitHub. Ignitersworld Lab. Traverse and Filter Method find Find the key on descendants of each element in the current set of matched elements in a jsonQ object.

Syntax :. Manipulation Method value It set value for each element of current set of matched element in jsonQ object. The value of each element of current set should be string or array. Matthew", "Mrs. William", "Mrs. Edward", "Mrs. Timothy", "Mrs. Jason", "Mrs. Daniel", "Mrs.

George", "Mrs. Brian", "Mrs. Frank", "Mrs. Larry", "Mrs. Scott", "Mrs. Charles", "Mrs. It can be chained but need to be refreshed before any other method is called. After any manipulation method you must call refresh method while chaining or if you have already cached any jsonQ object. Return Method value Return value of all matched element in a jsonQ object in a array. Following senarios an elm can be used as qualifier.

If elm is a function than each element of current set in jsonQ object will be passed on function to check weather it is satisfying qualifier condition or not. Then the index of first element of current set which have key value pair defined in qualifier will be returned.

If current set of jsonQ object is an array of array and elem is array or string. Then the index of first element of current set which have all elements of qualifier will be returned. Syntax : jsonQ. Limited only to json data types. Qualifier A qualifier can be defined in following ways.

Use jsonQ The first thing you can do is use jsonQ, make your site awesome, spread the word and let me know you are using it.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Code Review Stack Exchange is a question and answer site for peer programmer code reviews. It only takes a minute to sign up. Bonus question: any way of sorting a JSON collection? I found with. Is that the best way?

Another way you can do it is to have the collection in an object, and use the primary identifier as key. This identifier is usually a unique identifier for that entity, like a user id. This is way faster than iterating over an array in search for a match. As far as I remember, accessing via a key only takes one operation, O 1 while iterating through an array would depend on the length of the array. Worst case is that your match is at the tip of the array, thus O n. This is only good when you try to get the set by the key.

Otherwise, you'd have to resort to other arrangements for other retrievals. As for sorting though, objects don't guarantee order, though browsers do sort them somehow. As far as I know, iterating through properties of an object in Firefox and Chrome yield different orders in the way they are arranged. I tend to generate a lookup dictionary as soon as I have the data. So in any case I only need to iterate the data once. Comparing with your approach, let's say we need to call getByKey multiple times, the total cost of iterating the data might actually be higher.

I suppose which approach being more suitable really depends on your own application or design. But I also find myself sometimes generating different lookup dictionaries from the same set of data, and I would still only need to iterate the data once.

As for the. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 6 years, 11 months ago. Active 6 years, 1 month ago. Viewed 89k times. Any suggestions? Tommy B.

How to parse and search JSON in JavaScript

You could insert a "break" after you "found" the element. If you really have 1 element, that matches. This would speed your code up for average cases. Active Oldest Votes. Joseph Joseph But if you take a look at the OP's code, getByKey only returns one result, thus we could assume that it is unique. If there were multiple keys, the result would be false, i.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Code Review Stack Exchange is a question and answer site for peer programmer code reviews. It only takes a minute to sign up. Bonus question: any way of sorting a JSON collection?

I found with. Is that the best way? Another way you can do it is to have the collection in an object, and use the primary identifier as key.

find key in json array javascript

This identifier is usually a unique identifier for that entity, like a user id. This is way faster than iterating over an array in search for a match. As far as I remember, accessing via a key only takes one operation, O 1 while iterating through an array would depend on the length of the array.

Worst case is that your match is at the tip of the array, thus O n. This is only good when you try to get the set by the key. Otherwise, you'd have to resort to other arrangements for other retrievals. As for sorting though, objects don't guarantee order, though browsers do sort them somehow.

As far as I know, iterating through properties of an object in Firefox and Chrome yield different orders in the way they are arranged. I tend to generate a lookup dictionary as soon as I have the data. So in any case I only need to iterate the data once.

find key in json array javascript

Comparing with your approach, let's say we need to call getByKey multiple times, the total cost of iterating the data might actually be higher. I suppose which approach being more suitable really depends on your own application or design. But I also find myself sometimes generating different lookup dictionaries from the same set of data, and I would still only need to iterate the data once.

As for the.

Saving User Input in JS Objects

Sign up to join this community.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Code Review Stack Exchange is a question and answer site for peer programmer code reviews. It only takes a minute to sign up. And in such a case where I had no control of the JSON data, how could I improve on my solution to iterate for selected user and iterate again through nested object's data? No, don't do that.

You take an explicit relationship in one data structure and make it implicit between two data structures. Instead, do:. Now the relationship is explicit, and you can iterate over the array more simply and safely than iterating over the keys. Safely because, if a property is added to Object. This has a bit more going on than is totally necessary. The outer loop is superfluous, since we only actually do something for one key.

How To Push JSON Object Into An Array Using JavaScript

The inner loop changes with our new data structure. Also, we can do a bit of reorganization to help performance a bit. We will also change the if statement into a guard clause to clarify the code path. This relies on a newer ES5 featureso polyfill or replace with equivalent loops if you need to support older browsers see below. Also, this code does not exactly give the output you specified, FYI.

Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 5 years, 7 months ago.

Active 5 years, 7 months ago. Viewed k times. Pretty sure at some point in dev I had an array of users, however that's a new question as to how to retrieve the data as described. Care to offer a hint? Active Oldest Votes. Thank you again - much appreciated! I'm still studying itbut as I said there's a user selection and the json contains the data for multiple users, so I used the outer loop to specify.

We can just index in using the property name. So if selUser is "User02", myObj[selUser] will pull up the data for user Sign up or log in Sign up using Google.The find method returns the value of the first element in the provided array that satisfies the provided testing function.

The source for this interactive example is stored in a GitHub repository. The value of the first element in the array that satisfies the provided testing function. Otherwise, undefined is returned. The find method executes the callback function once for each index of the array until the callback returns a truthy value.

If so, find immediately returns the value of that element. Otherwise, find returns undefined. This means it may be less efficient for sparse arrays, compared to methods that only visit assigned values. If a thisArg parameter is provided to findit will be used as the this value inside each invocation of the callback. If it is not provided, then undefined is used. The find method does not mutate the array on which it is called, but the function provided to callback can.

If so, the elements processed by find are set before the first invocation of callback. The following example finds an element in the array that is a prime number or returns undefined if there is no prime number :. The following examples show that nonexistent and deleted elements are visited, and that the value passed to the callback is their value when visited:.

However, you can polyfill Array. If you need to support truly obsolete JavaScript engines that don't support Object. Get the latest and greatest from MDN delivered straight to your inbox. Sign in to enjoy the benefits of an MDN account.

The compatibility table in this page is generated from structured data. Last modified: Mar 13,by MDN contributors. Related Topics.Return value: It return a boolean denoting if the object has the specified property as own property. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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JavaScript | Check if a key exists inside a JSON object

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Load Comments.Help to translate the content of this tutorial to your language! Updating such toString every time can become a pain. We could try to loop over properties in it, but what if the object is complex and has nested objects in properties? It is described as in RFC standard. Initially it was made for JavaScript, but many other languages have libraries to handle it as well. The resulting json string is called a JSON-encoded or serialized or stringified or marshalled object.

We are ready to send it over the wire or put into a plain data store. Please note that a JSON-encoded object has several important differences from the object literal:. Here, the conversion fails, because of circular reference: room. Most of the time, JSON. But if we need to fine-tune the replacement process, like to filter out circular references, we can use the second argument of JSON. Here we are probably too strict. The property list is applied to the whole object structure.

find key in json array javascript

So the objects in participants are empty, because name is not in the list. Now everything except occupiedBy is serialized. But the list of properties is quite long.

Or undefined if the value is to be skipped. To ignore occupiedBythe code below returns undefined :. It is applied recursively. The value of this inside replacer is the object that contains the current property. The first call is special. In other words, the first key, value pair has an empty key, and the value is the target object as a whole. The third argument of JSON. Previously, all stringified objects had no indents and extra spaces.

The space argument is used exclusively for a nice output. Here we can see that date 1 became a string.


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