fix(ansi): whitespace handling on the last line (#287)

This commit fixes a bug where the last line of a wrapped string would
preserve spaces at the end of the line and might hard wrap the line
with spaces only. This commit changes the behavior to remove any
whitespace at the end of the line.

Fixes: #286

ansi/wrap.go

@@ -378,14 +378,17 @@ func Wrap(s string, limit int, breakpoints string) string {
 		i++
 	}
 
-	if word.Len() != 0 {
-		// Preserve ANSI wrapped spaces at the end of string
+	if wordLen == 0 {
 		if curWidth+space.Len() > limit {
-			buf.WriteByte('\n')
+			curWidth = 0
+		} else {
+			// preserve whitespaces
+			buf.Write(space.Bytes())
 		}
-		addSpace()
+		space.Reset()
 	}
-	buf.Write(word.Bytes())
+
+	addWord()
 
 	return buf.String()
 }

ansi/wrap_test.go

@@ -181,7 +181,7 @@ var wrapCases = []struct {
 	{
 		name:     "extra space style",
 		input:    "\x1b[mfoo \x1b[m",
-		expected: "\x1b[mfoo\n \x1b[m",
+		expected: "\x1b[mfoo\x1b[m",
 		width:    3,
 	},
 	{