Concat means add. The concat() method is used to marge 2 or more array
Filter means filter. array.filter() method returns a new array with all elements that pass the test implemented by the provided function.
The Math.floor() function returns the largest integer less than or equal to a given number.
The number.parseFloat() method parses an argument and returns a floating-point number. If a number cannot be parsed from the argument, it returns NaN.
This method using for string value converted from upper case to lower case. If we want to do string lowerCase then we will use this method.
Array.shift() method removes the first element from an array and returns that removed element. This method changes the length of the array.if you want to delete the first element from the array then you will apply this method.
unshift() the method adds one or more elements to the beginning of an array and returns the new length of the array.
pop() method deleted the last element from an array and returns that element. This method changes the length of the array. if we want to delete the last elements or information then we will call this method.
map() the method makes a new array populated with the results of calling a provided function on every element in the calling array.