Literals in JavaScript: Array, Object, String

 Literals represent fixed values in JavaScript. Here we'll talk about these three Literals mainly:

      1. Array
      2. Object
      3. String

1. Array:
         An array is a collection of elements enclosed in square brackets( [] ).

        Example

         const arr = ['a', 'b', 'c']

        To get the actual length of the array use length property as 

        console.log(arr.length) //output: 3

Consider another example:

       const arr = ['a', , 'b', ,]
       console.log(arr.length) //output: 4

       This is because, if you put two commas in a row in array, the array leaves an empty slot.

Note: If you include a trailing comma at the end of the list of elements, the comma is ignored.

2. Object:
        An Object literal is a list of zero or more pairs of property names and associated values of an object, enclose in curly braces({}).

       Example:

                  const = {name1:"value1", name2:"value2", ...}

      To access the values using the name in an object:

                 const p = {uid:1618, process:'notepad'}
                 console.log(p.uid) //output:1618
                 console.log(p['pid']) //output:1618

Note: property names which are not a valid identifier cannot be accessed using dot(.) property. But they can be accessed using bracket notation.

       Example:

                 const p ={ ' ':"empty", '&':'and' }
                 console.log(p.' ') //Syntax Error
                 console.log(p[' ']) //output:empty

3. String:
        A string literal is a sequence or zero or more characters enclosed within either double(") quotes or single(') quote.

       Example: 'hello', "world", "tour's"

       length property is used to get the actual length of the string as:

                   console.log('hello'.length) //output:5

       To combine the values of string and variable together, instead of concatenation we can use template literal enclose in bach-tick(`).

       Example:

                   let name = 'Narendra'
                   console.log( `hello ${name}` ) //output: hello Narendra

       Note: If you want to store a long string value, instead of writing all of them on a single line, you can write it on multiple line using a backlash. The string will escape a line break by preceding it with backlash as:

               const welcomeMsg = 'hello there \
                 welcome to our \
                 page\
                 Think design and Create.'
               console.log(welcomeMsg)
               //Output: hello there welcome to our page Think design and Create

Continue Learning: Falsy values and Error Handling