added separate prediate file

src/immutable.js

@@ -1,22 +1,8 @@
 'use strict'
 
-// The interface all immutable objects implement
-var interfaceFns = ['get', 'has', 'assoc', 'dissoc']
-
-// Predicate that indicates whether an object is
-var isImmutable = function(o){
-
-    if ( typeof o !== 'object' || o === null ) return false
-
-    for ( var i = 0, len = interfaceFns.length; i < len; i += 1 )
-        if ( typeof o[interfaceFns[i]] !== 'function' ) return false
-
-    if ( o.immutable !== true ) return false
-    return true
-}
 
 module.exports = {
     object: require('./object'),
     array: require('./array'),
-    isImmutable: isImmutable
+    isImmutable: require('./predicate')
 }

src/predicate.js

@@ -0,0 +1,16 @@
+// The interface all immutable objects implement
+var interfaceFns = ['get', 'has', 'assoc', 'dissoc']
+
+// Predicate that indicates whether an object is
+var isImmutable = function(o){
+
+    if ( typeof o !== 'object' || o === null ) return false
+
+    for ( var i = 0, len = interfaceFns.length; i < len; i += 1 )
+        if ( typeof o[interfaceFns[i]] !== 'function' ) return false
+
+    if ( o.immutable !== true ) return false
+    return true
+}
+
+module.exports = isImmutable

test/immutable-test.js

@@ -5,33 +5,6 @@ describe('immutable', function(){
 	it('should export API', function(){
 		a.equal(im.object, require('../src/object'))
 		a.equal(im.array, require('../src/array'))
+        a.equal(im.isImmutable, require('../src/predicate'))
 	})
-
-    describe('isImmutable', function(){
-        it('should return true on immutable objects', function(){
-            a.equal(im.isImmutable(im.object()), true)
-            a.equal(im.isImmutable(im.array()), true)
-        })
-
-        it('should return false on data that has an immutable flag', function(){
-            var fake = { immutable: true }
-            a.equal(im.isImmutable(im.object()), true)
-            a.equal(im.isImmutable(im.array()), true)
-        })
-
-        it('should require get, set, has, assoc and dissoc to be functions, along with an immutable flag', function(){
-            var noop = function(){}
-            var convincingFake = { immutable: true, get: noop, set: noop, assoc: noop, dissoc: noop, has: noop }
-
-            a.equal(im.isImmutable(convincingFake), true)
-        })
-
-        it('should return false on all js primitives', function(){
-            a.equal(im.isImmutable(null), false)
-            a.equal(im.isImmutable(undefined), false)
-            a.equal(im.isImmutable('foo'), false)
-            a.equal(im.isImmutable(1), false)
-            a.equal(im.isImmutable(true), false)
-        })
-    })
 })

test/predicate-test.js

@@ -0,0 +1,33 @@
+var a = require('assert')
+var isImmutable = require('../src/predicate')
+var im = require('..')
+
+
+describe('isImmutable', function(){
+    it('should return true on immutable objects', function(){
+        a.equal(isImmutable(im.object()), true)
+        a.equal(isImmutable(im.array()), true)
+    })
+
+    it('should return false on data that has an immutable flag', function(){
+        var fake = { immutable: true }
+        a.equal(isImmutable(fake), false)
+        a.equal(isImmutable(fake), false)
+    })
+
+    it('should require get, set, has, assoc and dissoc to be functions, along with an immutable flag', function(){
+        var noop = function(){}
+        var convincingFake = { immutable: true, get: noop, set: noop, assoc: noop, dissoc: noop, has: noop }
+
+        a.equal(isImmutable(convincingFake), true)
+    })
+
+    it('should return false on all js primitives', function(){
+        a.equal(isImmutable(null), false)
+        a.equal(isImmutable(undefined), false)
+        a.equal(isImmutable('foo'), false)
+        a.equal(isImmutable(1), false)
+        a.equal(isImmutable(true), false)
+    })
+})
+