JSON.md

JSON

Find all prime numbers in an array

const array = [-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13];

function isPrime(num) {
  for (let i = 2; num > i; i++) {
    if (num % i === 0) {
      return false; 
    }
  }
  return num > 1; 
}

console.log(array.filter(isPrime)); // [2, 3, 5, 7, 11, 13]

---

JSON stands for JavaScript Object Notation. JSON is a lightweight data interchange format. JSON is language independent. JSON is "self-describing" and easy to understand. In JSON, data is represented as key-alue pairs, where the keys are strings and the values can be strings, numbers, objects, arrays, booleans, or null. It is often used in web applications to transmit data in a structred way between the client and the server.

JSON Example

This JSON syntax defines an employees object: an array of 3 employees records (objects):

{
  "employees": [
  {"firstName":"John", "lastName":"Doe"},
  {"firstName":"Anna", "lastName":"Smith"},
  {"firstName":"Peter", "lastName":"Jones"}
  ]
}

The JSON format is syntactically identical to the code for creating JavaScript Objects. Because of this similarity, a JavaScript program can easily convert JSON data into native JavaScript objects.

JSON Syntax Rules

• Data is name/value pairs
• Data is separated by commas
• Curly braces hold objects
• Square brackets hold arrays

JSON Data - A Name and a Value

JSON data is written as name/value pairs, just like JavaScript Object properties. A name/value pair consists of a filed name (in double quotes), followed by a colon, followed by a value:

"firstName": "Jason"

JSON Objects

JSON objects are written inside curly braces. Just like in JavaScript, objects can contain multiple name/value pairs: {"firstName": "John", "lastName": "Doe"}

JSON Arrays

JSON arrays are written inside square brackets. Just like JavaScript, an array can contain objects:

"employees":[
  {"firstName":"John", "lastName":"Doe"},
  {"firstName":"Anna", "lastName":"Smith"},
  {"firstName":"Peter", "lastName":"Jones"}
]

---

Filtering invalid entries from JSON

The following examples use filter() to create a filterd JSON of all elements with non-zero, numeric id.

fjgh,jt## Filtering invalid entries from JSON The following examples use filter() to create a filterd JSON of all elements with non-zero, numeric id.