Important Javascript methods you need to know
Array Methods
1.Shift()
- This method is used to remove the first element from an array.While pop() method removes the last element.
Example : let items=[‘first’,’second’,’third’];
items.shift();
console.log(items); //output : items=[‘second’,’third’]
2. Unshift()
- This method is used to add a new element at the beginning of an array.While push() adds at the end of an array.
Example : let items=[‘second’,’third’];
items.unshift(‘first’);
console.log(items); //output : items=[‘first’‘second’,’third’]
3. Reverse()
-This method is used to reverse the order of the elements in an array.
Example : let items=[‘first’,’second’,’third’];
items.reverse();
console.log(items); //output : items=[’third’,’second’,’first’]
4. Slice()
-This method is used to cut a certain portion of an array without changing the original array.It returns a new array with the sliced elements.
Example : let items=[‘first’,’second’,’third’,’four’,’five’];
const slicedItems= items.slice(1,3);
console.log(slicedItems); //output : items=[’second’,’third’]
console.log(items); //output : items=[‘first’,’second’,’third’,’four’,’five’]
String methods
- trim()
-this method is used to remove whitespaces from the beginning and ending of a string.
Example : const word=’’ Hey MR Iron Man! “;
console.log(word.trim()); //output : ‘’Hey MR Iron Man!”
- indexOf()
-this method is used to get the index of a certain searched value from a string.It takes the first occurance of the searched value.
- charAt()
- this method is used to get an individual character from a string.
Example : const animal=’’dog’’;
console.log(animal.charAt(2)); // output : “a”
Math methods
- Math.round()
- This method returns the value of the given number rounded to the nearest integer.
Example : console.log(Math.round(.9)); //output 1
2.Math.sqrt()
- This method returns the positive square root of the given number
Example : console.log(Math.sqrt(49)); //output 7
3.Math.max() and Math.min()
-these methods return the maximum and minimum number from an array.
Example : let array=[1,2,3,4,5];
console.log(array.Math.max()); //output 5
console.log(array.Math.min()); //output 1
