Update what-is-json.md

locale/en/knowledge/javascript-conventions/what-is-json.md

@@ -14,11 +14,13 @@ has become the defacto standard for the web. JSON can be represented
 as either a list of values, e.g. an Array, or a hash of properties and
 values, e.g. an Object.
 
-    // a JSON array
-    ["one", "two", "three"]
+```json
+// a JSON array
+["one", "two", "three"]
 
-    // a JSON object
-    { "one": 1, "two": 2, "three": 3 }
+// a JSON object
+{ "one": 1, "two": 2, "three": 3 }
+```
 
 ## Encoding and Decoding
 
@@ -29,28 +31,32 @@ available on the `JSON` object that is available in the global scope.
 `JSON.stringify` takes a javascript object or array and returns a
 serialized string in the JSON format.
 
-    var data = {
-      name: "John Doe"
-      , age: 32
-      , title: "Vice President of JavaScript"
-    }
+```js
+const data = {
+  name: "John Doe",
+  age: 32,
+  title: "Vice President of JavaScript"
+}
 
-    var jsonStr = JSON.stringify(data);
+const jsonStr = JSON.stringify(data);
 
-    console.log(jsonStr);
+console.log(jsonStr);
 
-    // prints '{"name":"John Doe","age":32,"title":"Vice President of JavaScript"}'
+// prints '{"name":"John Doe","age":32,"title":"Vice President of JavaScript"}'
+```
 
 `JSON.parse` takes a JSON string and decodes it to a javascript data
 structure.
 
-    var jsonStr = '{"name":"John Doe","age":32,"title":"Vice President of JavaScript"}';
+```js
+const jsonStr = '{"name":"John Doe","age":32,"title":"Vice President of JavaScript"}';
 
-    var data = JSON.parse(jsonStr);
+const data = JSON.parse(jsonStr);
 
-    console.log(data.title);
+console.log(data.title);
 
-    // prints 'Vice President of JavaScript'
+// prints 'Vice President of JavaScript'
+```
 
 ## What is valid JSON?
 
@@ -67,38 +73,42 @@ format. There are several gotchas that can produce invalid JSON as well.
 
 These are all examples of valid JSON.
 
-    {"name":"John Doe","age":32,"title":"Vice President of JavaScript"}
+```json
+{"name":"John Doe","age":32,"title":"Vice President of JavaScript"}
 
-    ["one", "two", "three"]
+["one", "two", "three"]
 
-    // nesting valid values is okay
-    {"names": ["John Doe", "Jane Doe"] }
+// nesting valid values is okay
+{"names": ["John Doe", "Jane Doe"] }
 
-    [ { "name": "John Doe"}, {"name": "Jane Doe"} ]
+[ { "name": "John Doe"}, {"name": "Jane Doe"} ]
 
-    {} // empty hash
+{} // empty hash
 
-    [] // empty list
+[] // empty list
 
-    null
+null
 
-    { "key": "\uFDD0" } // unicode escape codes
+{ "key": "\uFDD0" } // unicode escape codes
+```
 
 These are all examples of bad JSON formatting.
 
-    { name: "John Doe", 'age': 32 } // name and age should be in double quotes
+```json
+{ name: "John Doe", 'age': 32 } // name and age should be in double quotes
 
-    [32, 64, 128, 0xFFF] // hex numbers are not allowed
+[32, 64, 128, 0xFFF] // hex numbers are not allowed
 
-    { "name": "John Doe", age: undefined } // undefined is an invalid value
+{ "name": "John Doe", "age": undefined } // undefined is an invalid value
 
-    // functions and dates are not allowed
-    { "name": "John Doe"
-      , "birthday": new Date('Fri, 26 Aug 2011 07:13:10 GMT')
-      , "getName": function() {
-          return this.name;
-      }
-    }
+// functions and dates are not allowed
+{ "name": "John Doe",
+  "birthday": new Date('Fri, 26 Jan 2019 07:13:10 GMT'),
+  "getName": function() {
+      return this.name;
+  }
+}
+```
 
 Calling `JSON.parse` with an invalid JSON string will result in a
 SyntaxError being thrown. If you are not sure of the validity of your
@@ -111,16 +121,26 @@ seem to make sense at first. But remember that JSON is a data format,
 not a format for transferring complex javascript objects along with
 their functionality.
 
+## JSON Validators
+
+As JSON has become the most widely used data formate with well-defined rules to abide by, there are many validators available to assist your workflow:
+
+* **Online Validators**: If you are just playing around with JSON or checking someone's JSON (without IDEs/editors) then online validators could be of great help. For instance: [jsonlint.com](https://jsonlint.com) is a good online JSON validator and reformatter.
+* **npm Packages**: If you are working with a team and want JSON Validation baked into your project or simply like to automate validation in your workflow then the large collection of npm packages are at your disposal. For instance: [jsonlint](https://www.npmjs.com/package/jsonlint) is a pure JavaScript version of the service provided at `jsonlint.com`.
+* **Plugins for IDEs/editors**: There are many plugins/extensions available for most of the IDEs/editors which validate JSON for you. Some editors like `VS Code` come with JSON IntelliSense & Validation out of the box.
+
 ## JSON in other languages
 
 Although JSON was inspired by the simplicity of javascript data
 structures, it's use is not limited to the javascript language. Many
 other languages have methods of transferring native hashes and lists
 into stringified JSON objects. Here's a quick example in ruby.
 
-    require 'json'
+```ruby
+require 'json'
 
-    data = { :one => 1 }
-    puts data.to_json
+data = { :one => 1 }
+puts data.to_json
 
-    # prints "{ \"one\": 1 }"
+# prints "{ \"one\": 1 }"
+```