No longer calling transformations multiple times for array values.

README.md

@@ -31,30 +31,24 @@ make test
 
 Transforms the given object by mapping it against the given transformation recursively.
 
-If `obj` is an array and `transformation` is an array, returns an array of the results of applying each transformation in the `transformation` array to the respective object in the `obj` array:
+If `obj` is an object and `transformation` is an object, returns a new object with each property set to the result of applying the property of the `transformation` to the respective property of the `obj`:
 
 ```javascript
 function upper(s) {return s.toUpperCase();}
 function lower(s) {return s.toLowerCase();}
-var result = transform(['Foo', 'Bar', 'Qux'], [upper, lower]);
-console.log(result); // ['FOO', 'bar', 'Qux']
-```
-
-If `obj` is an array and `transformation` is not an array, returns an array of the results of applying the `transformation` to each object in the `obj` array:
-
-```javascript
-function upper(s) {return s.toUpperCase();}
-var result = transform(['Foo', 'Bar', 'Qux'], upper);
-console.log(result); // ['FOO', 'BAR', 'QUX']
+var result = transform({a: 'Foo', b: 'Bar', c: 'Qux'}, {a: upper, b: lower});
+console.log(result); // {a: 'FOO', b: 'bar', c: 'Qux'}
 ```
 
-If `obj` is an object and `transformation` is an object, returns a new object with each property set to the result of applying the property of the `transformation` to the respective property of the `obj`:
+If `obj` is an array and `transformation` is an array or object, returns a new array with each item set to the result of applying the matching property or item of the `transformation` to the respective item in the `obj` array:
 
 ```javascript
 function upper(s) {return s.toUpperCase();}
 function lower(s) {return s.toLowerCase();}
-var result = transform({a: 'Foo', b: 'Bar', c: 'Qux'}, {a: upper, b: lower});
-console.log(result); // {a: 'FOO', b: 'bar', c: 'Qux'}
+var result1 = transform(['Foo', 'Bar', 'Qux'], {0: upper, 2: lower});
+console.log(result1); // ['FOO', 'Bar', 'qux']
+var result2 = transform(['Foo', 'Bar', 'Qux'], [upper, undefined, lower]);
+console.log(result2); // ['FOO', 'Bar', 'qux']
 ```
 
 If `transformation` is a `Function`, returns the result of calling it with the given `obj` as argument:

index.js

@@ -1,16 +1,9 @@
-/*! transform-object 0.1.2 Original author Alan Plum <me@pluma.io>. Released into the Public Domain under the UNLICENSE. @preserve */
+/*! transform-object 0.2.0 Original author Alan Plum <me@pluma.io>. Released into the Public Domain under the UNLICENSE. @preserve */
 module.exports = transform;
 
 function transform(obj, transformer) {
-  if (Array.isArray(obj)) {
-    return Array.isArray(transformer) ? obj.map(function(value, i) {
-      return transform(value, transformer[i]);
-    }) : obj.map(function(value) {
-      return transform(value, transformer);
-    });
-  }
   if (typeof transformer === 'object' && typeof obj === 'object') {
-    var result = {};
+    var result = Array.isArray(obj) ? [] : {};
     Object.keys(obj).forEach(function(key) {
       result[key] = transform(obj[key], transformer[key]);
     });

package.json

@@ -1,6 +1,6 @@
 {
   "name": "transform-object",
-  "version": "0.1.2",
+  "version": "0.2.0",
   "author": "Alan Plum <me@pluma.io>",
   "description": "Transforms objects.",
   "licenses": {
@@ -21,11 +21,11 @@
   "dependencies": {
   },
   "devDependencies": {
-    "mocha": "~1.17",
+    "mocha": "~1.18",
     "expect.js": "~0.3",
     "jshint": "~2.4",
     "istanbul": "~0.2",
-    "coveralls": "~2.8"
+    "coveralls": "~2.10"
   },
   "main": "index.js",
   "scripts": {

spec/transform.spec.js

@@ -4,21 +4,25 @@ var expect = require('expect.js'),
 
 function upper(s) {return s.toUpperCase();}
 function lower(s) {return s.toLowerCase();}
+function map(fn) {return function(arr) {return arr.map(fn);};}
 
 describe('transform(Array, Array)', function() {
   it('returns an array', function() {
     expect(transform([], [])).to.be.an('array');
   });
   it('applies each transformation to each matching item', function() {
-    expect(transform(['Foo', 'Bar', 'Qux'], [upper, lower]))
-    .to.eql(['FOO', 'bar', 'Qux']);
+    expect(transform(['Foo', 'Bar', 'Qux'], [upper, undefined, lower]))
+    .to.eql(['FOO', 'Bar', 'qux']);
   });
 });
 
-describe('transform(Array, *)', function() {
-  it('applies the transformation to each item', function() {
-    expect(transform(['Foo', 'Bar', 'Qux'], upper))
-    .to.eql(['FOO', 'BAR', 'QUX']);
+describe('transform(Array, Object)', function() {
+  it('returns an array', function() {
+    expect(transform([], {})).to.be.an('array');
+  });
+  it('applies each transformation to each matching item', function() {
+    expect(transform(['Foo', 'Bar', 'Qux'], {0: upper, 2: lower}))
+    .to.eql(['FOO', 'Bar', 'qux']);
   });
 });
 
@@ -29,8 +33,23 @@ describe('transform(Object, Object)', function() {
   });
 });
 
+describe('transform(Array, Function)', function() {
+  it('passes the array to the function', function() {
+    var called = false,
+      arg = [];
+    transform(arg, function(fnArg) {
+      expect(fnArg).to.equal(arg);
+      called = true;
+    });
+    expect(called).to.equal(true);
+  });
+  it('returns the result of the function', function() {
+    expect(transform(['foo', 'bar', 'qux'], map(upper))).to.eql(['FOO', 'BAR', 'QUX']);
+  });
+});
+
 describe('transform(*, Function)', function() {
-  it('passes the object to the function', function() {
+  it('passes the value to the function', function() {
     var called = false,
       arg = {};
     transform(arg, function(fnArg) {
@@ -45,7 +64,7 @@ describe('transform(*, Function)', function() {
 });
 
 describe('transform(*, undefined)', function() {
-  it('returns the object', function() {
+  it('returns the value', function() {
     var arg = {};
     expect(transform(arg, undefined)).to.equal(arg);
   });