add countGraphemes()

src/index.ts

@@ -24,7 +24,12 @@ export { isRegExp, escapeRegExpString } from "./regexp";
 export { addAll } from "./set";
 export { SortedArray } from "./SortedArray";
 export { asc, desc } from "./sorting";
-export { uppercaseFirst, lowercaseFirst, length } from "./string";
+export {
+  uppercaseFirst,
+  lowercaseFirst,
+  length,
+  countGraphemes,
+} from "./string";
 export { TrieMap } from "./TrieMap";
 export { UnsafeMap } from "./UnsafeMap";
 export type {

src/string.ts

@@ -21,12 +21,19 @@ export function lowercaseFirst(str: string): string {
 }
 
 /**
- * Get the number of characters in a string with customizable value for tabs.
+ * Get the number of characters/graphemes in a string.
+ */
+export function countGraphemes(text: string): number {
+  return Array.from(new Intl.Segmenter().segment(text)).length;
+}
+
+/**
+ * Get the number of characters/graphemes in a string.
  */
 export function length(text: string, tabSize: number): number {
   let size = 0;
-  for (const char of text) {
-    if (char === "\t") {
+  for (const { segment } of new Intl.Segmenter().segment(text)) {
+    if (segment === "\t") {
       size += tabSize;
     } else {
       size++;

test/string.test.ts

@@ -1,4 +1,9 @@
-import { lowercaseFirst, uppercaseFirst, length } from "../src/string";
+import {
+  lowercaseFirst,
+  uppercaseFirst,
+  length,
+  countGraphemes,
+} from "../src/string";
 
 describe("String", () => {
   describe("capitalizeFirst()", () => {
@@ -25,4 +30,11 @@ describe("String", () => {
       expect(length("Hello\n🤡", 2)).toBe(7);
     });
   });
+
+  describe("countGraphemes()", () => {
+    it("counts graphemes", () => {
+      expect(countGraphemes("ABC")).toBe(3);
+      expect(countGraphemes("Hello\n🤡")).toBe(7);
+    });
+  });
 });