Add "To Base62" and "From Base62" operations

src/core/operations/ToBase62.mjs

@@ -0,0 +1,54 @@
+/**
+ * @author tcode2k16 [tcode2k16@gmail.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import BigNumber from "bignumber.js";
+import Utils from "../Utils";
+import {toHexFast} from "../lib/Hex";
+
+/**
+ * To Base62 operation
+ */
+class ToBase62 extends Operation {
+
+    /**
+     * ToBase62 constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "To Base62";
+        this.module = "Default";
+        this.description = "encode string to base62";
+        this.infoURL = "https://en.wikipedia.org/wiki/List_of_numeral_systems";
+        this.inputType = "string";
+        this.outputType = "string";
+        this.args = [];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    run(input, args) {
+        if (input.length < 1) return "";
+
+        const ALPHABET = Utils.expandAlphRange("0-9A-Za-z").join("");
+        const BN = BigNumber.clone({ ALPHABET });
+
+        input = Utils.strToByteArray(input);
+        input = toHexFast(input);
+        input = input.toUpperCase();
+
+        const number = new BN(input, 16);
+
+        return number.toString(62);
+    }
+
+}
+
+export default ToBase62;