ESM: Ported Base58, Base and BCD operations

src/core/operations/ToBase58.mjs

@@ -0,0 +1,85 @@
+/**
+ * @author tlwr [toby@toby.codes]
+ * @copyright Crown Copyright 2017
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import Utils from "../Utils";
+import OperationError from "../errors/OperationError";
+import {ALPHABET_OPTIONS} from "../lib/Base58";
+
+/**
+ * To Base58 operation
+ */
+class ToBase58 extends Operation {
+
+    /**
+     * ToBase58 constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "To Base58";
+        this.module = "Default";
+        this.description = "Base58 (similar to Base64) is a notation for encoding arbitrary byte data. It differs from Base64 by removing easily misread characters (i.e. l, I, 0 and O) to improve human readability.<br><br>This operation encodes data in an ASCII string (with an alphabet of your choosing, presets included).<br><br>e.g. <code>hello world</code> becomes <code>StV1DL6CwTryKyV</code><br><br>Base58 is commonly used in cryptocurrencies (Bitcoin, Ripple, etc).";
+        this.inputType = "byteArray";
+        this.outputType = "string";
+        this.args = [
+            {
+                "name": "Alphabet",
+                "type": "editableOption",
+                "value": ALPHABET_OPTIONS
+            }
+        ];
+    }
+
+    /**
+     * @param {byteArray} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        let alphabet = args[0] || ALPHABET_OPTIONS[0].value,
+            result = [0];
+
+        alphabet = Utils.expandAlphRange(alphabet).join("");
+
+        if (alphabet.length !== 58 ||
+            [].unique.call(alphabet).length !== 58) {
+            throw new OperationError("Error: alphabet must be of length 58");
+        }
+
+        if (input.length === 0) return "";
+
+        input.forEach(function(b) {
+            let carry = (result[0] << 8) + b;
+            result[0] = carry % 58;
+            carry = (carry / 58) | 0;
+
+            for (let i = 1; i < result.length; i++) {
+                carry += result[i] << 8;
+                result[i] = carry % 58;
+                carry = (carry / 58) | 0;
+            }
+
+            while (carry > 0) {
+                result.push(carry % 58);
+                carry = (carry / 58) | 0;
+            }
+        });
+
+        result = result.map(function(b) {
+            return alphabet[b];
+        }).reverse().join("");
+
+        while (result.length < input.length) {
+            result = alphabet[0] + result;
+        }
+
+        return result;
+    }
+
+}
+
+export default ToBase58;