Javascript Practice 23: JS Hero - String: indexOf()

 

Question: 

 

Write a function indexOfIgnoreCase taking two strings and determining the first occurrence of the second string in the first string. The function should be case insensitive.

Example: indexOfIgnoreCase('bit','it') and indexOfIgnoreCase('bit','IT') should return 1.

 

 

 

 

 

Answer: 

 

 

 function indexOfIgnoreCase (s1, s2) {

let x = s1.toLowerCase();
let y = s2.toLowerCase();
let z = x.indexOf(y);
return z;

};

 

> function indexOfIgnoreCase has to perform two tasks

> it has to ignore the case (lower or upper) of both the strings

> it has to return the position of the first occurrence of a specified value in a string

> we first define a variable x and initialize it with a value which converts the s1 parameter to the lower case

> we then define another variable y and initialize it with a value which converts the s2 parameter to the lower case

> since the indexOf() method is case sensitive it is better to convert the strings to a similar case 

> we then declare a final variable z and initialize it with the value x.indexOf(y)

where x = lower case of s1

where y = lower case of s2

x.indexOf(y) will give us the first occurrence of y in x

> finally we return the value of z  

> indexOf() method returns the position of the first occurrence of a specified value in a string. 

> it is case sensitive

> returns -1 if the value to search for never occurs