Fix a duplicate character in the urlSafeCharacters list (#10)

Author: Yanis Benson

index.js

@@ -1,7 +1,7 @@
 'use strict';
 const crypto = require('crypto');
 
-const urlSafeCharacters = 'abcdefjhijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._~'.split('');
+const urlSafeCharacters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._~'.split('');
 
 const generateForCustomCharacters = (length, characters) => {
 	// Generating entropy is faster than complex math operations, so we use the simplest way

test.js

@@ -1,39 +1,58 @@
 import test from 'ava';
 import cryptoRandomString from '.';
 
+// Probailistic, result is always less than or equal to actual set size, chance it is less is below 1e-256 for sizes up to 32656
+const generatedCharacterSetSize = (options, targetSize) => {
+	const set = new Set();
+	const length = targetSize * 640;
+	const string = cryptoRandomString({...options, length});
+
+	for (let i = 0; i < length; i++) {
+		set.add(string[i]);
+	}
+
+	return set.size;
+};
+
 test('main', t => {
 	t.is(cryptoRandomString({length: 0}).length, 0);
 	t.is(cryptoRandomString({length: 10}).length, 10);
 	t.is(cryptoRandomString({length: 100}).length, 100);
 	t.regex(cryptoRandomString({length: 100}), /^[a-f\d]*$/); // Sanity check, probabilistic
+	t.is(generatedCharacterSetSize({}, 16), 16);
 });
 
 test('hex', t => {
 	t.is(cryptoRandomString({length: 0, type: 'hex'}).length, 0);
 	t.is(cryptoRandomString({length: 10, type: 'hex'}).length, 10);
 	t.is(cryptoRandomString({length: 100, type: 'hex'}).length, 100);
 	t.regex(cryptoRandomString({length: 100, type: 'hex'}), /^[a-f\d]*$/); // Sanity check, probabilistic
+	t.is(generatedCharacterSetSize({type: 'hex'}, 16), 16);
 });
 
 test('base64', t => {
 	t.is(cryptoRandomString({length: 0, type: 'base64'}).length, 0);
 	t.is(cryptoRandomString({length: 10, type: 'base64'}).length, 10);
 	t.is(cryptoRandomString({length: 100, type: 'base64'}).length, 100);
 	t.regex(cryptoRandomString({length: 100, type: 'base64'}), /^[a-zA-Z\d/+]*$/); // Sanity check, probabilistic
+	t.is(generatedCharacterSetSize({type: 'base64'}, 64), 64);
 });
 
 test('url-safe', t => {
 	t.is(cryptoRandomString({length: 0, type: 'url-safe'}).length, 0);
 	t.is(cryptoRandomString({length: 10, type: 'url-safe'}).length, 10);
 	t.is(cryptoRandomString({length: 100, type: 'url-safe'}).length, 100);
 	t.regex(cryptoRandomString({length: 100, type: 'url-safe'}), /^[a-zA-Z\d._~-]*$/); // Sanity check, probabilistic
+	t.is(generatedCharacterSetSize({type: 'url-safe'}, 66), 66);
 });
 
 test('characters', t => {
 	t.is(cryptoRandomString({length: 0, characters: '1234'}).length, 0);
 	t.is(cryptoRandomString({length: 10, characters: '1234'}).length, 10);
 	t.is(cryptoRandomString({length: 100, characters: '1234'}).length, 100);
 	t.regex(cryptoRandomString({length: 100, characters: '1234'}), /^[1-4]*$/); // Sanity check, probabilistic
+	t.is(generatedCharacterSetSize({characters: '1234'}, 4), 4);
+	t.is(generatedCharacterSetSize({characters: '0123456789'}, 10), 10);
 });
 
 test('argument errors', t => {