How do I make the first letter of a string uppercase in JavaScript?

Question

How do I make the first letter of a string uppercase, but not change the case of any of the other letters?

For example:

• \"this is a test\"

Answer 1

SHORTEST 3 solutions, 1 and 2 handle cases when s string is "", null and undefined:

 s&&s[0].toUpperCase()+s.slice(1)        // 32 char

 s&&s.replace(/./,s[0].toUpperCase())    // 36 char - using regexp

'foo'.replace(/./,x=>x.toUpperCase())    // 31 char - direct on string, ES6

let s='foo bar';

console.log( s&&s[0].toUpperCase()+s.slice(1) );

console.log( s&&s.replace(/./,s[0].toUpperCase()) );

console.log( 'foo bar'.replace(/./,x=>x.toUpperCase()) );