javascript multiline regexp replace

Question

"foo\r\nbar".replace(/(foo).+/m, "bar")

Hello. I can not understand why this code does not replace foo on bar

Answer 1

I can not understand why this code does not replace foo on bar

Because the dot . explicitly does not match newline characters.

This would work:

"foo\r\nbar".replace(/foo[\s\S]+/m, "bar")

because newline characters count as whitespace ( \\s ).

Note that the parentheses around foo are superfluous, grouping has no benefits here.

Answer 2

JavaScript does not support a dot-all modifier. A common replacement is:

"foo\r\nbar".replace(/(foo)[\s\S]+/, "bar")

/m makes ^ and $ behave correctly, but has not effect on . .