Standard library / String methods · on the one-page reference
String methods
Stable — pure slice operations, no I/O, conformance-covered.
Called directly on any string value.
| API | Type |
|---|---|
s.length · s + t · s.concat(t, …) | int · concatenation · string (variadic) |
s.split(sep, limit?) | (string | regex, int) → string[] (splits on a string or a regex separator; at most limit parts for the string form) |
s.slice(start, end?) · s.substring(start, end) | → string |
s.indexOf(sub, from?) · s.lastIndexOf(sub) · s.includes(sub, from?) | → int · int · bool |
s.search(regex) | regex → int (index of the first match, or −1) |
s.startsWith(prefix, pos?) · s.endsWith(suffix, end?) | → bool |
s.localeCompare(t) | string → int (−1 / 0 / 1 by byte order; use as a sort comparator) |
s.toUpperCase() · s.toLowerCase() · s.trim() | → string |
s.trimStart() · s.trimEnd() | → string |
s.repeat(n) · s.padStart(len, pad?) · s.padEnd(len, pad?) | → string (pad defaults to a space) |
s.replace(from, to) · s.replaceAll(from, to) | → string (from is a string or a regex; a regex with the g flag replaces every match, otherwise the first) |
s.charAt(i) · s.at(i) · s.charCodeAt(i) · s.codePointAt(i) | → string · string · int · int (at allows negative index; byte-oriented) |
String.isEmpty(s) · String.contains(s, sub) | → bool |
String.compare(a, b) | (string, string) → int (−1 / 0 / 1; use as an array sort comparator) |
String(x) | number | bool | string → string (global conversion) |
Boolean(x) | number | bool | string → bool (truthiness: nonzero / nonempty / itself) |
Number(x) | number | bool | string → f64 (NaN if a string doesn't parse) |
String.fromCharCode(code, …) · String.fromCodePoint(code, …) | (int, …) → string (one byte per code, each & 0xFF) |