add isStrongPassword method

README.md

@@ -150,6 +150,7 @@ Validator                               | Description
 **isSurrogatePair(str)**                | check if the string contains any surrogate pairs chars.
 **isUppercase(str)**                    | check if the string is uppercase.
 **isSlug**                              | Check if the string is of type slug. `Options` allow a single hyphen between string. e.g. [`cn-cn`, `cn-c-c`]
+**isStrongPassword(str, requirementOptions?, scoringOptions?)**   | Check if a password is strong or not. Allows for custom requirements or scoring rules. If `returnScore` is true, then the function returns an integer score for the password rather than a boolean.<br/>Default options: <br/>`{ minLength: 8, minLowercase: 1, minUppercase: 1, minNumbers: 1, minSymbols: 1, returnScore: false, pointsPerUnique: 1, pointsPerRepeat: 0.5, pointsForContainingLower: 10, pointsForContainingUpper: 10, pointsForContainingNumber: 10, pointsForContainingSymbol: 10 }`
 **isTaxID(str, locale)**                | Check if the given value is a valid Tax Identification    Number. Default locale is `en-US`
 **isURL(str [, options])**              | check if the string is an URL.<br/><br/>`options` is an object which defaults to `{ protocols: ['http','https','ftp'], require_tld: true, require_protocol: false, require_host: true, require_valid_protocol: true, allow_underscores: false, host_whitelist: false, host_blacklist: false, allow_trailing_dot: false, allow_protocol_relative_urls: false, disallow_auth: false }`.<br/><br/>require_protocol - if set as true isURL will return false if protocol is not present in the URL.<br/>require_valid_protocol - isURL will check if the URL's protocol is present in the protocols option.<br/>protocols - valid protocols can be modified with this option.<br/>require_host - if set as false isURL will not check if host is present in the URL.<br/>allow_protocol_relative_urls - if set as true protocol relative URLs will be allowed.
 **isUUID(str [, version])**             | check if the string is a UUID (version 3, 4 or 5).

src/index.js

@@ -114,6 +114,7 @@ import isWhitelisted from './lib/isWhitelisted';
 import normalizeEmail from './lib/normalizeEmail';
 
 import isSlug from './lib/isSlug';
+import isStrongPassword from './lib/isStrongPassword';
 
 const version = '13.1.1';
 
@@ -211,6 +212,7 @@ const validator = {
   normalizeEmail,
   toString,
   isSlug,
+  isStrongPassword,
   isTaxID,
   isDate,
 };

src/lib/isStrongPassword.js

@@ -0,0 +1,96 @@
+import merge from './util/merge';
+import assertString from './util/assertString';
+
+const upperCaseRegex = /^[A-Z]$/;
+const lowerCaseRegex = /^[a-z]$/;
+const numberRegex = /^[0-9]$/;
+const symbolRegex = /^[-#!$%^&*()_+|~=`{}\[\]:";'<>?,.\/ ]$/;
+
+const defaultOptions = {
+  minLength: 8,
+  minLowercase: 1,
+  minUppercase: 1,
+  minNumbers: 1,
+  minSymbols: 1,
+  returnScore: false,
+  pointsPerUnique: 1,
+  pointsPerRepeat: 0.5,
+  pointsForContainingLower: 10,
+  pointsForContainingUpper: 10,
+  pointsForContainingNumber: 10,
+  pointsForContainingSymbol: 10,
+};
+
+/* Counts number of occurances of each char in a string
+ * could be moved to util/ ?
+*/
+function countChars(str) {
+  let result = {};
+  Array.from(str).forEach((char) => {
+    let curVal = result[char];
+    if (curVal) {
+      result[char] += 1;
+    } else {
+      result[char] = 1;
+    }
+  });
+  return result;
+}
+
+/* Return information about a password */
+function analyzePassword(password) {
+  let charMap = countChars(password);
+  let analysis = {
+    length: password.length,
+    uniqueChars: Object.keys(charMap).length,
+    uppercaseCount: 0,
+    lowercaseCount: 0,
+    numberCount: 0,
+    symbolCount: 0,
+  };
+  Object.keys(charMap).forEach((char) => {
+    if (upperCaseRegex.test(char)) {
+      analysis.uppercaseCount += charMap[char];
+    } else if (lowerCaseRegex.test(char)) {
+      analysis.lowercaseCount += charMap[char];
+    } else if (numberRegex.test(char)) {
+      analysis.numberCount += charMap[char];
+    } else if (symbolRegex.test(char)) {
+      analysis.symbolCount += charMap[char];
+    }
+  });
+  return analysis;
+}
+
+function scorePassword(analysis, scoringOptions) {
+  let points = 0;
+  points += analysis.uniqueChars * scoringOptions.pointsPerUnique;
+  points += (analysis.length - analysis.uniqueChars) * scoringOptions.pointsPerRepeat;
+  if (analysis.lowercaseCount > 0) {
+    points += scoringOptions.pointsForContainingLower;
+  }
+  if (analysis.uppercaseCount > 0) {
+    points += scoringOptions.pointsForContainingUpper;
+  }
+  if (analysis.numberCount > 0) {
+    points += scoringOptions.pointsForContainingNumber;
+  }
+  if (analysis.symbolCount > 0) {
+    points += scoringOptions.pointsForContainingSymbol;
+  }
+  return points;
+}
+
+export default function isStrongPassword(str, options = null) {
+  assertString(str);
+  const analysis = analyzePassword(str);
+  options = merge(options || {}, defaultOptions);
+  if (options.returnScore) {
+    return scorePassword(analysis, options);
+  }
+  return analysis.length >= options.minLength
+        && analysis.lowercaseCount >= options.minLowercase
+        && analysis.uppercaseCount >= options.minUppercase
+        && analysis.numberCount >= options.minNumbers
+        && analysis.symbolCount >= options.minSymbols;
+}

test/validators.js

@@ -8561,6 +8561,28 @@ describe('Validators', () => {
     });
   });
 
+  it('should validate strong passwords', () => {
+    test({
+      validator: 'isStrongPassword',
+      valid: [
+        '%2%k{7BsL"M%Kd6e',
+        'EXAMPLE of very long_password123!',
+        'mxH_+2vs&54_+H3P',
+        '+&DxJ=X7-4L8jRCD',
+        'etV*p%Nr6w&H%FeF',
+      ],
+      invalid: [
+        '',
+        'password',
+        'hunter2',
+        'hello world',
+        'passw0rd',
+        'password!',
+        'PASSWORD!',
+      ],
+    });
+  });
+
   it('should validate base64URL', () => {
     test({
       validator: 'isBase64',