hjzheng · April 20, 2020 06:24 · Apr 20, 2020
diff --git a/base58.ts b/base58.ts
@@ -0,0 +1,36 @@
+function base58(encodeMap) {
+  function base58encode(int64: string): string {
+    let num = BigInt(int64)
+    const base = 58n
+
+    let res = ''
+    while (num >= base) {
+      res += encodeMap[num % base]
+      num = num / base
+    }
+    res += encodeMap[num]
+    return res
+      .split('')
+      .reverse()
+      .join('')
+  }
+
+  /**
+   * base58 to int64
+   * @param {string} base58
+   * @returns {string} int64
+   */
+  function base58decode(base58: string): string {
+    let num = 0n
+    for (let i = 0; i < base58.length; i++) {
+      num = num * 58n + BigInt(encodeMap.indexOf(base58[i]))
+    }
+    return num.toString()
+  }
+  return {
+    encode: base58encode,
+    decode: base58decode,
+  }
+}
+
+export default base58