extract-params - npm Package Compare versions

Comparing version 1.0.0 to 2.0.0

lib/extractParams.js

@@ -8,6 +8,17 @@ var paramRegex = /:[a-zA-Z]+/g;
 
-module.exports = function extractParams(str, pattern) {
+function identity(params) {
+  return params;
+}
+
+module.exports = function extractParams(str, pattern, transform) {
+  if (typeof transform === 'undefined') {
+    transform = identity;
+  } else if (typeof transform !== 'function') {
+    throw new Error('\'transform\' must be a function');
+    return null;
+  }
+
   var valuesRegex = new RegExp('^' + pattern.split(paramRegex).map(function(patternPart) {
     return escapeRegexCharacters(patternPart);
-  }).join('(.+)'));
+  }).join('(.+)') + '$');
 
@@ -23,3 +34,3 @@ var valuesMatch = str.match(valuesRegex);
   if (paramsMatch === null) {
-    return {};
+    return transform({});
   }
@@ -31,6 +42,6 @@
 
-  return valuesMatch.slice(1).reduce(function(result, value, index) {
+  return transform(valuesMatch.slice(1).reduce(function(result, value, index) {
     result[params[index]] = value;
     return result;
-  }, {});
+  }, {}));
 };

lib/extractParamsInFirstMatch.js

@@ -7,7 +7,7 @@ var extractParams = require('./extractParams');
   for (var i = 0; i < patternsCount; i++) {
-    var params = extractParams(str, patterns[i]);
+    var params = extractParams(str, patterns[i].pattern, patterns[i].transform);
 
     if (params !== null) {
       return {
-        pattern: patterns[i],
+        patternIndex: i,
         params: params
@@ -14,0 +14,0 @@ };

package.json

 {
   "name": "extract-params",
-  "version": "1.0.0",
+  "version": "2.0.0",
   "description": "Extract parameters from a string based on a pattern",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -32,10 +32,12 @@ <a href="https://codeship.com/projects/119982" target="_blank">
 
-* [`extractParams(str, pattern)`](#extractParams)
+* [`extractParams(str, pattern, transform)`](#extractParams)
 * [`extractParamsInFirstMatch(str, patterns)`](#extractParamsInFirstMatch)
 
 <a name="extractParams"></a>
-### extractParams(str, pattern)
+### extractParams(str, pattern, transform)
 
 Tests whether `str` matches the given parameterized `pattern`, and returns a key-value object of parameters and their values in case of a successful match.
 
+An optional `transform` function can be passed to manipulate the extracted params. If `transform` returns `null`, the match fails. `transform` can be used, for example, to lowercase the values in `params`, or to validate them (return `null` if validation fails).
+
 `pattern` parameters must be in the following format: `:camelCase`
@@ -81,6 +83,27 @@
 
+#### Example 3
+
+```js
+var params = extractParams(
+  '/users/1234/friends/456/photo',
+  '/users/:userId/friends/:friendId/photo',
+  function(params) {
+    var userId = parseInt(params.userId, 10);
+    
+    return userId >= 1 && userId <= 999 ? params : null;
+  }
+);
+
+/* 
+  Returns:
+    null
+    
+  because userId > 999
+*/
+```
+
 <a name="extractParamsInFirstMatch"></a>
 ### extractParamsInFirstMatch(str, patterns)
 
-Tests whether `str` matches one of the parameterized `patterns`. If none of the `patterns` match, `extractParamsInFirstMatch` returns `null`. Otherwise, it returns the matching pattern and its parameters.
+Tests whether `str` matches one of the parameterized `patterns`. Every pattern can have an optional `transform` function. If none of the `patterns` match, `extractParamsInFirstMatch` returns `null`. Otherwise, it returns the matching pattern index and its parameters.
 
@@ -93,7 +116,7 @@ #### Example 1
   [
-    '/users/:userId/friends/:friendId/photo',
-    '/users/:userId/friends/:friendId',
-    '/users/:userId/friends',
-    '/users/:userId',
-    '/users'
+    { pattern: '/users/:userId/friends/:friendId/photo' },
+    { pattern: '/users/:userId/friends/:friendId' },
+    { pattern: '/users/:userId/friends' },
+    { pattern: '/users/:userId' },
+    { pattern: '/users' }
   ]
@@ -105,3 +128,3 @@ );
     {
-      pattern: '/users/:userId',
+      patternIndex: 3,
       params: {
@@ -120,7 +143,7 @@ userId: '123'
   [
-    '/users/:userId/friends/:friendId/photo',
-    '/users/:userId/friends/:friendId',
-    '/users/:userId/friends',
-    '/users/:userId',
-    '/users'
+    { pattern: '/users/:userId/friends/:friendId/photo' },
+    { pattern: '/users/:userId/friends/:friendId' },
+    { pattern: '/users/:userId/friends' },
+    { pattern: '/users/:userId' },
+    { pattern: '/users' }
   ]
@@ -137,3 +160,39 @@ );
 
+#### Example 3
 
+```js
+function userIdValidator(params) {
+  if (!('userId' in params)) {
+    return params;
+  }
+
+  // Without this check, '/users/1234/friends/567' would match '/users/:userId'
+  // with { userId: '1234/friends/567' }
+  if (!(/^\d+$/.test(params.userId))) {
+    return null;
+  }
+
+  var userId = parseInt(params.userId, 10);
+
+  return userId >= 1 && userId <= 999 ? params : null;
+}
+var params = extractParamsInFirstMatch(
+  '/users/1234/friends/567',
+  [
+    { pattern: '/users/:userId/friends/:friendId/photo', transform: userIdValidator },
+    { pattern: '/users/:userId/friends/:friendId', transform: userIdValidator },
+    { pattern: '/users/:userId/friends', transform: userIdValidator },
+    { pattern: '/users/:userId', transform: userIdValidator },
+    { pattern: '/users' }
+  ]
+);
+
+/* 
+  Returns:
+    null
+    
+  because userId > 999
+*/
+```
+
 ## Running Tests
@@ -140,0 +199,0 @@

test/extractParams.js

@@ -18,2 +18,8 @@ var expect = require('chai').expect;
   {
+    should: 'return null if there is match but not at the end',
+    str: 'language-elm-is-awesome',
+    pattern: 'language-:lang-is',
+    result: null
+  },
+  {
     should: 'return {} if there is match but the pattern has no parameters',
@@ -25,2 +31,21 @@ str: 'react-is-awesome',
   {
+    should: 'return use the transform function if there is match but the pattern has no parameters',
+    str: 'react-is-awesome',
+    pattern: 'react-is-awesome',
+    transform: function(params) {
+      var newParams = {
+        mood: 'awesome'
+      };
+
+      for (var param in params) {
+        newParams[param] = params[param];
+      }
+
+      return newParams;
+    },
+    result: {
+      mood: 'awesome'
+    }
+  },
+  {
     should: 'extract single parameter',
@@ -50,2 +75,31 @@ str: 'my-name-is-Misha',
     }
+  },
+  {
+    should: 'transform the extracted params using the transform function',
+    str: '/users/123/friends/456/photo',
+    pattern: '/users/:userId/friends/:friendId/photo',
+    transform: function(params) {
+      var newParams = {};
+
+      for (var param in params) {
+        newParams[param] = '**' + params[param] + '**';
+      }
+
+      return newParams;
+    },
+    result: {
+      userId: '**123**',
+      friendId: '**456**'
+    }
+  },
+  {
+    should: 'fail the match if the transform function returns null',
+    str: '/users/1234/friends/456/photo',
+    pattern: '/users/:userId/friends/:friendId/photo',
+    transform: function(params) {
+      var userId = parseInt(params.userId, 10);
+
+      return userId >= 1 && userId <= 999 ? params : null;
+    },
+    result: null
   }
@@ -57,5 +111,5 @@ ];
     it(testCase.should, function() {
-      expect(extractParams(testCase.str, testCase.pattern)).to.deep.equal(testCase.result);
+      expect(extractParams(testCase.str, testCase.pattern, testCase.transform)).to.deep.equal(testCase.result);
     });
   });
 });

test/extractParamsInFirstMatch.js

 var expect = require('chai').expect;
 var extractParamsInFirstMatch = require('../lib/extractParamsInFirstMatch');
 
+function userIdValidator(params) {
+  if (!('userId' in params)) {
+    return params;
+  }
+
+  // Without this check, '/users/1234/friends/567' would match '/users/:userId'
+  // with { userId: '1234/friends/567' }
+  if (!(/^\d+$/.test(params.userId))) {
+    return null;
+  }
+
+  var userId = parseInt(params.userId, 10);
+
+  return userId >= 1 && userId <= 999 ? params : null;
+}
+
 var testCases = [
@@ -15,5 +31,5 @@ {
     patterns: [
-      'he-said-that-:language-is-:description',
-      '/user/:userId/friends/:friendId',
-      ':who-knows-that-:language-is-great'
+      { pattern: 'he-said-that-:language-is-:description' },
+      { pattern: '/user/:userId/friends/:friendId' },
+      { pattern: ':who-knows-that-:language-is-great' }
     ],
@@ -26,10 +42,10 @@ result: null
     patterns: [
-      '/users/:userId/friends/:friendId/photo',
-      '/users/:userId/friends/:friendId',
-      '/users/:userId/friends',
-      '/users/:userId',
-      '/users'
+      { pattern: '/users/:userId/friends/:friendId/photo' },
+      { pattern: '/users/:userId/friends/:friendId' },
+      { pattern: '/users/:userId/friends' },
+      { pattern: '/users/:userId' },
+      { pattern: '/users' }
     ],
     result: {
-      pattern: '/users/:userId',
+      patternIndex: 3,
       params: {
@@ -39,2 +55,14 @@ userId: '123'
     }
+  },
+  {
+    should: 'use the transform function to return the first match',
+    str: '/users/1234/friends/456',
+    patterns: [
+      { pattern: '/users/:userId/friends/:friendId/photo', transform: userIdValidator },
+      { pattern: '/users/:userId/friends/:friendId', transform: userIdValidator },
+      { pattern: '/users/:userId/friends', transform: userIdValidator },
+      { pattern: '/users/:userId', transform: userIdValidator },
+      { pattern: '/users' }
+    ],
+    result: null
   }
@@ -41,0 +69,0 @@ ];

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Improved metrics

Total package byte prevSize

13121

increased by48.98%

Lines of code

226

increased by56.94%

Number of lines in readme file

201

increased by41.55%

No dependency changes