time: add more detailed error descriptions, add custom format parsing with time.parse_format (#18257)

vlib/builtin/js/string.js.v

@@ -106,10 +106,13 @@ pub fn (s string) clone() string {
 	return string(s.str)
 }
 
+// contains returns `true` if the string contains `substr`.
+// See also: [`string.index`](#string.index)
 pub fn (s string) contains(substr string) bool {
 	return bool(s.str.includes(substr.str))
 }
 
+// contains_any returns `true` if the string contains any chars in `chars`.
 pub fn (s string) contains_any(chars string) bool {
 	sep := ''
 	res := chars.str.split(sep.str)
@@ -121,6 +124,26 @@ pub fn (s string) contains_any(chars string) bool {
 	return false
 }
 
+// contains_only returns `true`, if the string contains only the characters in `chars`.
+pub fn (s string) contains_only(chars string) bool {
+	if chars.len == 0 {
+		return false
+	}
+	for ch in s {
+		mut res := 0
+		for c in chars {
+			if ch == c {
+				res++
+				break
+			}
+		}
+		if res == 0 {
+			return false
+		}
+	}
+	return true
+}
+
 pub fn (s string) contains_any_substr(chars []string) bool {
 	if chars.len == 0 {
 		return true

vlib/builtin/js/string_test.js.v

@@ -404,6 +404,13 @@ fn test_contains_any() {
 	assert !''.contains_any('')
 }
 
+fn test_contains_only() {
+	assert '23885'.contains_only('0123456789')
+	assert '23gg885'.contains_only('01g23456789')
+	assert !'hello;'.contains_only('hello')
+	assert !''.contains_only('')
+}
+
 fn test_contains_any_substr() {
 	s := 'Some random text'
 	assert s.contains_any_substr(['false', 'not', 'rand'])