@@ -47,6 +47,8 @@ Top JavaScript interview questions
4747| 39 | [ How do we add comments in javascript] ( #39-how-do-we-add-comments-in-javascript ) |
4848| 40 | [ What is the use of typeof operator] ( #40-what-is-the-use-of-typeof-operator ) |
4949| 41 | [ Is JavaScript case-sensitive] ( #41-is-javascript-case-sensitive ) |
50+ | 42 | [ Difference between push() and unshift()] ( #42-difference-between-push-and-unshift ) |
51+ | 43 | [ Difference between pop() and shift()] ( #43-difference-between-pop-and-shift ) |
5052
5153### 1. What is JavaScript
5254* JavaScript is a scripting language used to create dynamic and interactive websites. It is supported by all major web browsers.
@@ -625,6 +627,43 @@ Yes, JavaScript is a case-sensitive language. For e.g., the variables firstName
625627let firstName = " Surbhi"
626628console .log (firstname); // output ========> Uncaught ReferenceError: firstname is not defined
627629` ` `
630+
631+ ### 42. Difference between push() and unshift()
632+ Both are used to add elements to an array, but they add elements in different ways.
633+
634+ **push()** - It adds one or more elements to the end of an array and returns the new length of the array.
635+ ` ` `
636+ let arr = [1 ,2 ,3 ,4 ];
637+ let newArr = arr .push (5 ,6 ,7 );
638+ console .log (newArr); // output ========> 7
639+ console .log (arr); // output ========> [1, 2, 3, 4, 5, 6, 7]
640+ ` ` `
641+ **unshift()** - It adds one or more elements to the beginning of an array and returns the new length of the array.
642+ ` ` `
643+ let arr = [1 ,2 ,3 ,4 ];
644+ let newArr = arr .unshift (5 ,6 ,7 );
645+ console .log (newArr); // output ========> 7
646+ console .log (arr); // output ========> [5, 6, 7, 1, 2, 3, 4]
647+ ` ` `
648+
649+ ### 43. Difference between pop() and shift()
650+ Both are used to remove elements from an array, but they remove elements in different ways.
651+
652+ **pop()** - It removes the last element of an array and returns the removed element.
653+ ` ` `
654+ let arr = [1 ,2 ,3 ,4 ];
655+ let newArr = arr .pop ();
656+ console .log (newArr); // output ========> 4
657+ console .log (arr); // output ========> [1,2,3]
658+ ` ` `
659+
660+ **shift()** - It removes the first element of an array and returns the removed element.
661+ ` ` `
662+ let arr = [1 ,2 ,3 ,4 ];
663+ let newArr = arr .shift ();
664+ console .log (newArr); // output ========> 1
665+ console .log (arr); // output ========> [2,3,4]
666+ ` ` `
628667******************************In progress
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