JavaScript - Remove first n characters from string

We are required to write a JavaScript function that takes in a string and a number n and returns another string with first n characters removed from the string.

For example −

If the original string is −

const str = "this is a string"
and n = 5,

then the output should be −

const output = "is a string"

Let’s write the code for this function −

Following is the code −

const mobileNumber = '+915389534759385';
const secondNumber = '+198345985734';
const removeN = (str, num) => {
   const { length } = str;
   if(num > length){
      return str;
   };
   const newStr = str.substr(num, length - num);
   return newStr;
};
console.log(removeN(mobileNumber, 3));
console.log(removeN(secondNumber, 2));

Output

Following is the output in the console −

5389534759385
98345985734