diff --git a/lib/irc.js b/lib/irc.js
index 8a0eda7..abba9f5 100644
--- a/lib/irc.js
+++ b/lib/irc.js
@@ -264,7 +264,7 @@ const alphaNum = (() => {
 		return new RegExp(/^[a-zA-Z0-9]$/, "u");
 	}
 })();
-const space = new RegExp(/\s/);
+const space = new RegExp(/^\s$/);
 
 function isWordBoundary(ch) {
 	switch (ch) {
@@ -279,7 +279,7 @@ function isWordBoundary(ch) {
 
 function isURIPrefix(text) {
 	for (let i = text.length - 1; i >= 0; i--) {
-		if (text[i].search(space)) {
+		if (space.test(text[i])) {
 			text = text.slice(i);
 			break;
 		}