Add alphanumeric character set (#25)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>
sindresorhus · Sep 3, 2020 · a4c63c8 · a4c63c8
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Showing 4 changed files with 27 additions and 3 deletions.
diff --git a/index.d.ts b/index.d.ts
@@ -19,6 +19,8 @@ interface TypeOption {
 
 	The `ascii-printable` set contains all [printable ASCII characters](https://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters): ``!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~`` Useful for generating passwords where all possible ASCII characters should be used.
 
+	The `alphanumeric` set contains uppercase letters, lowercase letters, and digits: `ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789`. Useful for generating [nonce](https://developer.mozilla.org/en-US/docs/Web/API/HTMLOrForeignElement/nonce) values.
+
 	@example
 	```
 	cryptoRandomString({length: 10});
@@ -38,9 +40,12 @@ interface TypeOption {
 
 	cryptoRandomString({length: 10, type: 'ascii-printable'});
 	//=> '`#Rt8$IK>B'
+	
+	cryptoRandomString({length: 10, type: 'alphanumeric'});
+	//=> 'DMuKL8YtE7'
 	```
 	*/
-	type?: 'hex' | 'base64' | 'url-safe' | 'numeric' | 'distinguishable' | 'ascii-printable';
+	type?: 'hex' | 'base64' | 'url-safe' | 'numeric' | 'distinguishable' | 'ascii-printable' | 'alphanumeric';
 }
 
 interface CharactersOption {

diff --git a/index.js b/index.js
@@ -8,6 +8,7 @@ const urlSafeCharacters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0
 const numericCharacters = '0123456789'.split('');
 const distinguishableCharacters = 'CDEHKMPRTUWXY012458'.split('');
 const asciiPrintableCharacters = '!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~'.split('');
+const alphanumericCharacters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.split('');
 
 const generateForCustomCharacters = (length, characters) => {
 	// Generating entropy is faster than complex math operations, so we use the simplest way
@@ -77,7 +78,8 @@ const allowedTypes = [
 	'url-safe',
 	'numeric',
 	'distinguishable',
-	'ascii-printable'
+	'ascii-printable',
+	'alphanumeric'
 ];
 
 const createGenerator = (generateForCustomCharacters, generateRandomBytes) => ({length, type, characters}) => {
@@ -125,6 +127,10 @@ const createGenerator = (generateForCustomCharacters, generateRandomBytes) => ({
 		return generateForCustomCharacters(length, asciiPrintableCharacters);
 	}
 
+	if (type === 'alphanumeric') {
+		return generateForCustomCharacters(length, alphanumericCharacters);
+	}
+
 	if (characters.length === 0) {
 		throw new TypeError('Expected `characters` string length to be greater than or equal to 1');
 	}

diff --git a/readme.md b/readme.md
@@ -33,6 +33,9 @@ cryptoRandomString({length: 6, type: 'distinguishable'});
 cryptoRandomString({length: 10, type: 'ascii-printable'});
 //=> '`#Rt8$IK>B'
 
+cryptoRandomString({length: 10, type: 'alphanumeric'});
+//=> 'DMuKL8YtE7'
+
 cryptoRandomString({length: 10, characters: 'abc'});
 //=> 'abaaccabac'
 ```
@@ -62,7 +65,7 @@ Length of the returned string.
 
 Type: `string`\
 Default: `'hex'`\
-Values: `'hex' | 'base64' | 'url-safe' | 'numeric' | 'distinguishable' | 'ascii-printable'`
+Values: `'hex' | 'base64' | 'url-safe' | 'numeric' | 'distinguishable' | 'ascii-printable' | 'alphanumeric'`
 
 Use only characters from a predefined set of allowed characters.
 
@@ -72,6 +75,8 @@ The `distinguishable` set contains only uppercase characters that are not easily
 
 The `ascii-printable` set contains all [printable ASCII characters](https://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters): ``!"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~`` Useful for generating passwords where all possible ASCII characters should be used.
 
+The `alphanumeric` set contains uppercase letters, lowercase letters, and digits: `ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789`. Useful for generating [nonce](https://developer.mozilla.org/en-US/docs/Web/API/HTMLOrForeignElement/nonce) values.
+
 ##### characters
 
 Type: `string`\

diff --git a/test.js b/test.js
@@ -76,6 +76,14 @@ test('ascii-printable', t => {
 	t.regex(cryptoRandomString({length: 100, type: 'ascii-printable'}), /^[!"#$%&'()*+,-./\d:;<=>?@A-Z[\\\]^_`a-z{|}~]*$/); // Sanity check, probabilistic
 });
 
+test('alphanumeric', t => {
+	t.is(cryptoRandomString({length: 0, type: 'alphanumeric'}).length, 0);
+	t.is(cryptoRandomString({length: 10, type: 'alphanumeric'}).length, 10);
+	t.is(cryptoRandomString({length: 100, type: 'alphanumeric'}).length, 100);
+	t.regex(cryptoRandomString({length: 100, type: 'alphanumeric'}), /^[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789]*$/); // Sanity check, probabilistic
+	t.is(generatedCharacterSetSize({type: 'alphanumeric'}, 19), 62);
+});
+
 test('characters', t => {
 	t.is(cryptoRandomString({length: 0, characters: '1234'}).length, 0);
 	t.is(cryptoRandomString({length: 10, characters: '1234'}).length, 10);