feat: add numberToWords function

Author: AsadSaleh

numberToWords.ts

@@ -0,0 +1,94 @@
+function recursiveNumToWords(amount: number): string {
+  const numberInText = [
+    "",
+    "satu",
+    "dua",
+    "tiga",
+    "empat",
+    "lima",
+    "enam",
+    "tujuh",
+    "delapan",
+    "sembilan",
+    "sepuluh",
+    "sebelas",
+  ];
+
+  if (amount < 12) {
+    return numberInText[amount] as string;
+  }
+  if (amount < 20) {
+    return recursiveNumToWords(amount - 10) + " belas";
+  }
+  if (amount < 100) {
+    return (
+      recursiveNumToWords(Math.floor(amount / 10)) +
+      " puluh " +
+      recursiveNumToWords(amount % 10)
+    );
+  }
+  if (amount < 200) {
+    return "seratus " + recursiveNumToWords(amount - 100);
+  }
+  if (amount < 1_000) {
+    return (
+      recursiveNumToWords(Math.floor(amount / 100)) +
+      " ratus " +
+      recursiveNumToWords(amount % 100)
+    );
+  }
+  if (amount < 2_000) {
+    return "seribu " + recursiveNumToWords(amount - 1_000);
+  }
+  if (amount < 1_000_000) {
+    return (
+      recursiveNumToWords(Math.floor(amount / 1_000)) +
+      " ribu " +
+      recursiveNumToWords(amount % 1_000)
+    );
+  }
+  if (amount < 1_000_000_000) {
+    return (
+      recursiveNumToWords(Math.floor(amount / 1_000_000)) +
+      " juta " +
+      recursiveNumToWords(amount % 1_000_000)
+    );
+  }
+  if (amount < 1_000_000_000_000) {
+    return (
+      recursiveNumToWords(Math.floor(amount / 1_000_000_000)) +
+      " milyar " +
+      recursiveNumToWords(amount % 1_000_000_000)
+    );
+  }
+  if (amount < 1_000_000_000_000) {
+    return (
+      recursiveNumToWords(Math.floor(amount / 1_000_000_000_000)) +
+      " trilyun " +
+      recursiveNumToWords(amount % 1_000_000_000_000)
+    );
+  }
+  return "";
+}
+
+function trimExcessSpaces(input: string): string {
+  return input.replace(/ +/g, " ").trim();
+}
+
+function numberToWords(amount: number): string {
+  return trimExcessSpaces(recursiveNumToWords(amount));
+}
+
+// test
+// console.log(numberToWords(200_000));
+// console.log(numberToWords(250_000));
+// console.log(numberToWords(252_000));
+console.log(numberToWords(200_000) === "dua ratus ribu");
+console.log(numberToWords(250_000) === "dua ratus lima puluh ribu");
+console.log(numberToWords(252_000) === "dua ratus lima puluh dua ribu");
+console.log(numberToWords(2_000_000) === "dua juta");
+console.log(numberToWords(250_000_001) === "dua ratus lima puluh juta satu");
+console.log(
+  numberToWords(11_987_654) ===
+    "sebelas juta sembilan ratus delapan puluh tujuh ribu enam ratus lima puluh empat"
+);