For this, use toUpperCase() along with toLowerCase(). Following is the code −
Example
function capitalEveryFirstletter(subjectTitle) { return subjectTitle.split(' ') .map(st => st.charAt(0).toUpperCase() + st.slice(1).toLowerCase()) .join(' ');; } var subjectTitle="iNtroduction tO JavaScript ProgRAMMINg"; var output=capitalEveryFirstletter(subjectTitle); console.log("The result="+output);
To run the above program, you need to use the following command −
node fileName.js.
Here, my file name is demo74.js.
Output
This will produce the following output −
PS C:\Users\Amit\JavaScript-code> node demo74.js The result=Introduction To JavaScript Programming