Initial support for bitcoin and ripple alphabets

src/base58.js

@@ -1,9 +1,17 @@
-const alphabet = "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";
-const base = alphabet.length;
+const alphabets = {
+  flickr: "123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ",
+  bitcoin: "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz",
+  ripple: "rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz"
+};
+const base = alphabets.flickr.length;
 
 // Create a lookup table to fetch character index
-const alphabetLookup = [...alphabet].reduce((lookup, char, index) => {
-  lookup[char] = index;
+const alphabetLookups = Object.keys(alphabets).reduce((lookup, name) => {
+  lookup[name] = [...alphabets[name]].reduce((memo, char, index) => {
+    memo[char] = index;
+    return memo;
+  }, {});
+
   return lookup;
 }, {});
 
@@ -25,13 +33,13 @@ function assertString(str) {
   }
 }
 
-function assertBase58Character(character) {
-  if (alphabetLookup[character] === undefined) {
+function assertBase58Character(character, alphabet) {
+  if (alphabetLookups[alphabet][character] === undefined) {
     throw new Error("Value passed is not a valid Base58 string.");
   }
 }
 
-exports.int_to_base58 = exports.encode = function(num) {
+exports.int_to_base58 = exports.encode = function(num, alphabet = "flickr") {
   let str = "";
   let modulus;
 
@@ -41,18 +49,18 @@ exports.int_to_base58 = exports.encode = function(num) {
 
   while (num >= base) {
     modulus = num % base;
-    str = alphabet[modulus] + str;
+    str = alphabets[alphabet][modulus] + str;
     num = Math.floor(num / base);
   }
 
-  return alphabet[num] + str;
+  return alphabets[alphabet][num] + str;
 };
 
-exports.base58_to_int = exports.decode = function(str) {
+exports.base58_to_int = exports.decode = function(str, alphabet = "flickr") {
   assertString(str);
 
   return [...str].reverse().reduce((num, character, index) => {
-    assertBase58Character(character);
-    return num + alphabetLookup[character] * Math.pow(base, index);
+    assertBase58Character(character, alphabet);
+    return num + alphabetLookups[alphabet][character] * Math.pow(base, index);
   }, 0);
 };

test/base58.test.js

@@ -2,9 +2,9 @@ const assert = require("assert");
 const examples = require("./examples");
 const base58 = require("..");
 
-function exampleRunner(callback) {
-  Object.keys(examples).forEach(function(str) {
-    callback(str, examples[str]);
+function exampleRunner(alphabet, callback) {
+  Object.keys(alphabet).forEach(function(str) {
+    callback(str, alphabet[str]);
   });
 }
 
@@ -13,18 +13,20 @@ describe("Base58", function() {
     var valid = true;
     var count = 0;
 
-    exampleRunner(function(str, num) {
-      count++;
-      if (typeof str !== "string") {
-        valid = false;
-      }
-      if (typeof num !== "number") {
-        valid = false;
-      }
-    });
+    for (var alphabetName in examples.alphabets) {
+      exampleRunner(examples.alphabets[alphabetName], function(str, num) {
+        count++;
+        if (typeof str !== "string") {
+          valid = false;
+        }
+        if (typeof num !== "number") {
+          valid = false;
+        }
+      });
 
-    assert.strictEqual(count > 0, true, "Expected there to be examples");
-    assert.strictEqual(valid, true, "Expected the examples to be valid");
+      assert.strictEqual(count > 0, true, "Expected there to be examples");
+      assert.strictEqual(valid, true, "Expected the examples to be valid");
+    }
   });
 
   describe("backwards compatibility", function() {
@@ -38,17 +40,49 @@ describe("Base58", function() {
   });
 
   describe(".int_to_base58()", function() {
-    it("encodes number to Base58 string", function() {
-      exampleRunner(function(str, num) {
-        assert.strictEqual(base58.int_to_base58(num), str);
-      });
-    });
+    for (var alphabetName in examples.alphabets) {
+      describe("when using " + alphabetName + " alphabet", function() {
+        it("encodes number to Base58 string", function() {
+          exampleRunner(examples.alphabets[alphabetName], function(str, num) {
+            let result = base58.int_to_base58(num, alphabetName);
 
-    describe("when passed a string only containing numbers", function() {
-      it("encodes string after first converting it to an integer", function() {
-        exampleRunner(function(str, num) {
-          assert.strictEqual(base58.int_to_base58(num.toString()), str);
+            assert.strictEqual(result, str);
+          });
         });
+
+        describe("when passed a string only containing numbers", function() {
+          it("encodes string after first converting it to an integer", function() {
+            exampleRunner(examples.alphabets[alphabetName], function(str, num) {
+              let result = base58.int_to_base58(num.toString(), alphabetName);
+
+              assert.strictEqual(result, str);
+            });
+          });
+        });
+      });
+    }
+
+    describe("when alphabet is not specified", function() {
+      it("encodes number to Base58 string with flickr alphabet", function() {
+        exampleRunner(examples.alphabets.flickr, function(str, num) {
+          let result = base58.int_to_base58(num);
+
+          assert.strictEqual(result, str);
+        });
+      });
+
+      describe("when passed a string only containing numbers", function() {
+        it(
+          "encodes string with flickr alphabet " +
+            "after first converting it to an integer",
+          function() {
+            exampleRunner(examples.alphabets.flickr, function(str, num) {
+              let result = base58.int_to_base58(num.toString());
+
+              assert.strictEqual(result, str);
+            });
+          }
+        );
       });
     });
 
@@ -114,35 +148,81 @@ describe("Base58", function() {
   });
 
   describe(".base58_to_int()", function() {
-    it("decodes base58 string to number", function() {
-      exampleRunner(function(str, num) {
-        assert.strictEqual(base58.base58_to_int(str), num);
-      });
-    });
+    for (var alphabetName in examples.alphabets) {
+      describe("when using " + alphabetName + " alphabet", function() {
+        it("decodes base58 string to number", function() {
+          exampleRunner(examples.alphabets[alphabetName], function(str, num) {
+            let result = base58.base58_to_int(str, alphabetName);
 
-    describe("when passed a non string", function() {
-      it("throws an error", function() {
-        assert.throws(
-          function() {
-            base58.base58_to_int(123);
-          },
-          function(err) {
-            return err.message === "Value passed is not a string.";
-          }
-        );
-      });
-    });
+            assert.strictEqual(result, num);
+          });
+        });
 
-    describe("when passed a non base58 string", function() {
-      it("throws an error", function() {
-        assert.throws(
-          function() {
-            base58.base58_to_int(">_<");
-          },
-          function(err) {
-            return err.message === "Value passed is not a valid Base58 string.";
-          }
-        );
+        describe("when passed a non string", function() {
+          it("throws an error", function() {
+            assert.throws(
+              function() {
+                base58.base58_to_int(123, alphabetName);
+              },
+              function(err) {
+                return err.message === "Value passed is not a string.";
+              }
+            );
+          });
+        });
+
+        describe("when passed a non base58 string", function() {
+          it("throws an error", function() {
+            assert.throws(
+              function() {
+                base58.base58_to_int(">_<", alphabetName);
+              },
+              function(err) {
+                return (
+                  err.message === "Value passed is not a valid Base58 string."
+                );
+              }
+            );
+          });
+        });
+      });
+    }
+
+    describe("when alphabet is not specified", function() {
+      it("decodes base58 string to number with flickr alphabet", function() {
+        exampleRunner(examples.alphabets.flickr, function(str, num) {
+          let result = base58.base58_to_int(str);
+
+          assert.strictEqual(result, num);
+        });
+      });
+
+      describe("when passed a non string", function() {
+        it("throws an error", function() {
+          assert.throws(
+            function() {
+              base58.base58_to_int(123);
+            },
+            function(err) {
+              return err.message === "Value passed is not a string.";
+            }
+          );
+        });
+      });
+
+      describe("when passed a non base58 string", function() {
+        it("throws an error", function() {
+          assert.throws(
+            function() {
+              base58.base58_to_int(">_<");
+            },
+            function(err) {
+              return (
+                err.message === "Value passed is not a valid Base58 string."
+              );
+            }
+          );
+        });
       });
     });
   });