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JSON(JavaScript Object Notation) is a storage format that is completely language independent and it is used to store and transport data. It’s quite an important topic as the data which we fetch from external API usually consists of Arrays of elements which are in JSON format.
The syntax of JSON is quite similar to the Object literal syntax which also consists of name, value pairs. But here both names, as well as values, are quoted in inverted commas.
Let us look at the example below :
//Object literals syntax
let details = {
firstName : "John",
lastName : "Adams",
age : 27
}
//JSON syntax
{
"firstName" : "Mike",
"lastName" : "Bush",
"age" : 25
}
It is believed that in previous years XML format was widely used which has tags surrounding the data.The above mention JSON data in XML format is represented as below
<details>
<firstName>Mike</firstName>
<lastName>Bush</lastName>
<age>25</age>
</details>
As you can see the XML format is verbose as compare to JSON i.e. for a single value “Mike”, the name “firstName” is repeated twice for the opening and closing tags which is quite unnecessary. Also, the JSON can be parsed to Object literal which makes it faster to work with.
JSON is so popular that even JavaScript understands it and it has inbuilt functions to convert from JSON to object literal and vice versa.
JSON.stringify()
method to convert data from object literal format to JSON format const objectData = {
firstName : "Mike",
lastName : "Bush"
}
const JSONdata = JSON.stringify(objectData)
console.log(JSONdata)
Output:-
{"firstName":"Mike","lastName":"Bush"}
JSON.parse()
which converts JSON format data to Object literal formatconst JSONdata = '{ "firstName" : "Mike", "lastName" : "Bush"}';
const ObjectData = JSON.parse(JSONdata)
console.log(ObjectData)
Output:-
{firstName: "Mike", lastName: "Bush"}
This is what I learned when I started with JSON. Understanding fundamentals and the methods of JSON are important as they are an elemental part of accessing information with API.
Conclusion :
JSON.stringify()
Object --> JSONJSON.parse()
JSON --> ObjectThank you for your time for reading the article
This article was originally published on sarveshkadam.tech
#javascript #json
1604501887
this article is much worthy
1591611780
How can I find the correct ulimit values for a user account or process on Linux systems?
For proper operation, we must ensure that the correct ulimit values set after installing various software. The Linux system provides means of restricting the number of resources that can be used. Limits set for each Linux user account. However, system limits are applied separately to each process that is running for that user too. For example, if certain thresholds are too low, the system might not be able to server web pages using Nginx/Apache or PHP/Python app. System resource limits viewed or set with the NA command. Let us see how to use the ulimit that provides control over the resources available to the shell and processes.
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1591993440
We are going to build a full stack Todo App using the MEAN (MongoDB, ExpressJS, AngularJS and NodeJS). This is the last part of three-post series tutorial.
MEAN Stack tutorial series:
AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II)
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III) 👈 you are here
Before completing the app, let’s cover some background about the this stack. If you rather jump to the hands-on part click here to get started.
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1591989720
Welcome to this tutorial about RESTful API using Node.js (Express.js) and MongoDB (mongoose)! We are going to learn how to install and use each component individually and then proceed to create a RESTful API.
MEAN Stack tutorial series:
AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II) 👈 you are here
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III)
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1597723200
When I install s3cmd package on my FreeBSD system and try to use the s3cmd command I get the following error:
_ERROR: Test failed: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (ssl.c:1091)
How do I fix this problem on FreeBSD Unix system?
Amazon Simple Storage Service (s3 ) is object storage through a web service interface or API. You can store all sorts of files. FreeBSD is free and open-source operating systems. s3cmd is a command-line utility for the Unix-like system to upload, download files to AWS S3 service from the command line.
This error indicates that you don’t have packages correctly installed, especially SSL certificates. Let us see how to fix this problem and install s3cmd correctly on FreeBSD to get rid of the problem.
Search for s3cmd package:
$ pkg search s3cmd
Execute the following command and make sure you install Python 3.x package as Python 2 will be removed after 2020:
$ sudo pkg install py37-s3cmd-2.1.0
Updating FreeBSD repository catalogue...
FreeBSD repository is up to date.
All repositories are up to date.
Checking integrity... done (0 conflicting)
The following 8 package(s) will be affected (of 0 checked):
New packages to be INSTALLED:
libffi: 3.2.1_3
py37-dateutil: 2.8.1
py37-magic: 5.38
py37-s3cmd: 2.1.0
py37-setuptools: 44.0.0
py37-six: 1.14.0
python37: 3.7.8
readline: 8.0.4
Number of packages to be installed: 8
The process will require 118 MiB more space.
Proceed with this action? [y/N]: y
[rsnapshot] [1/8] Installing readline-8.0.4...
[rsnapshot] [1/8] Extracting readline-8.0.4: 100%
[rsnapshot] [2/8] Installing libffi-3.2.1_3...
....
..
[rsnapshot] [8/8] Extracting py37-s3cmd-2.1.0: 100%
=====
Message from python37-3.7.8:
--
Note that some standard Python modules are provided as separate ports
as they require additional dependencies. They are available as:
py37-gdbm databases/py-gdbm@py37
py37-sqlite3 databases/py-sqlite3@py37
py37-tkinter x11-toolkits/py-tkinter@py37
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1592610180
CentOS Linux 8.2 (2004) released. It is a Linux distribution derived from RHEL (Red Hat Enterprise Linux) 8.2 source code. CentOS was created when Red Hat stopped providing RHEL free. CentOS 8.2 gives complete control of its open-source software packages and is fully customized for research needs or for running a high-performance website without the need for license fees. Let us see what’s new in CentOS 8.2 (2004) and how to upgrade existing CentOS 8.1.1199 server to 8.2.2004 using the command line.
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