The syntax of the substr method is as below :
str.substr([start , length])
This method takes two arguments :
start : This is the start index from where the substring is required.
length : The length of the substring. If this value is not provided, it returns the substring to the end of the string.
If we call the substr method without start and length, it will return the same string. For example :
let str = "abcdefghijklmnopqrstuvwxyz"; console.log(str.substr()); console.log(str.substr(5)); console.log(str.substr(5,5));
The above program prints the below output :
abcdefghijklmnopqrstuvwxyz fghijklmnopqrstuvwxyz fghij
In the above example,
The first console.log statement prints the whole string because we are calling substr method without start and length.
The second console.log statement prints one substring to the end starting from the index 5.
The third console.log statement prints one substring of size 5 starting from the index 5.