Match and replace all tabs at the beginning of the line with four spaces

Question

I\'ve read some other questions and answers on the site, but all of them were a little different from what I\'m seeking: replace all tabs at the beginning of a string with four

Answer 1

First off, you are replacing both tabs and a non-word character which may not be a tab character necessarily with four spaces. You are not matching each \t character separately.

replace all tabs at the beginning of a string with four spaces

You could use y flag:

console.log(
  "\t\tHello, world!".replace(/\t/gy, '    ')
);

or without using y modifier (to support ancient browsers) you could go with a little more bit of code:

console.log(
  "\t\tHello, world!\t".replace(/\t|(.+)/gs, function(match, p1) {
      return p1 ? p1 : '    ';
  })
);