Merge pull request #457 from keropodium/map

Add map method: Creates a new string with the results of calling a pr…

Author: esamattis

README.markdown

@@ -769,6 +769,28 @@ toBoolean("true only at start", [/^true/]);
 // => true
 ```
 
+#### map(string, function) => string
+
+Creates a new string with the results of calling a provided function on every character of the given string.
+
+```javascript
+map("Hello world", function(x) {
+  return x;
+});
+// => "Hello world"
+
+map(12345, function(x) {
+  return x;
+});
+// => "12345"
+
+map("Hello world", function(x) {
+  if (x === 'o') x = 'O';
+  return x;
+});
+// => "HellO wOrld"
+```
+
 ### Library functions
 
 If you require the full library you can use chaining and aliases

exports.js

@@ -2,7 +2,7 @@ module.exports = function() {
   var result = {};
 
   for (var prop in this) {
-    if (!this.hasOwnProperty(prop) || prop.match(/^(?:include|contains|reverse|join)$/)) continue;
+    if (!this.hasOwnProperty(prop) || prop.match(/^(?:include|contains|reverse|join|map)$/)) continue;
     result[prop] = this[prop];
   }
 

index.js

@@ -76,6 +76,7 @@ s.toBoolean        = require('./toBoolean');
 s.exports          = require('./exports');
 s.escapeRegExp     = require('./helper/escapeRegExp');
 s.wrap             = require('./wrap');
+s.map              = require('./map');
 
 // Aliases
 s.strip     = s.trim;
@@ -88,6 +89,7 @@ s.contains  = s.include;
 s.q         = s.quote;
 s.toBool    = s.toBoolean;
 s.camelcase = s.camelize;
+s.mapChars  = s.map;
 
 
 // Implement chaining

map.js

@@ -0,0 +1,9 @@
+var makeString = require('./helper/makeString');
+
+module.exports = function(str, callback) {
+  str = makeString(str);
+
+  if (str.length === 0 || typeof callback !== 'function') return str;
+
+  return str.replace(/./g, callback);
+};

tests/map.js

@@ -0,0 +1,31 @@
+var equal = require('assert').equal;
+var map = require('../map');
+
+
+test('#map', function() {
+  equal(map('Hello world', function(x) {
+    return x;
+  }), 'Hello world');
+  equal(map(12345, function(x) {
+    return x;
+  }), '12345');
+  equal(map('Hello world', function(x) {
+    if (x === 'o') x = 'O';
+    return x;
+  }), 'HellO wOrld');
+  equal(map('', function(x) {
+    return x;
+  }), '');
+  equal(map(null, function(x) {
+    return x;
+  }), '');
+  equal(map(undefined, function(x) {
+    return x;
+  }), '');
+  equal(map('Hello world', ''), 'Hello world');
+  equal(map('Hello world', null), 'Hello world');
+  equal(map('Hello world', undefined), 'Hello world');
+  equal(map('', ''), '');
+  equal(map(null, null), '');
+  equal(map(undefined, undefined), '');
+});