redefine - npm Package Compare versions

Comparing version 0.1.1 to 0.1.2

build/redefine.js

 /*! (C) WebReflection *//** @preserve https://github.com/WebReflection/redefine */
-var _=this._=function(e,m,d){function n(a,r,c,d){if(!(c instanceof v))if(c instanceof w){var e=c._,h=f.call(c,p)?!!c[p]:!0,m=f.call(c,q)&&c[q],n=f.call(c,k)&&c[k],s;c[t]=function(){b[j]=e.call(s=this);b[p]=h;b[q]=m;b[k]=n;x(s,r,b);y(b);return s[r]}}else c=(u[j]=c,u);l(d||g.defaults||{},b);l(c,b);if(f.call(c,t)||f.call(c,z))delete b[k],delete b[j];x(a,r,b);y(b);delete u[j]}function v(a){l(a,this)}function w(a){this._="function"==typeof a?a:l(a,this)||a[j]}function g(a,b,c,d){if("string"==typeof b)n(a,
-b,c,d);else for(var e in b)f.call(b,e)&&n(a,e,b[e],c);return a}var p="configurable",q="enumerable",t="get",z="set",j="value",k="writable",x=e.defineProperty||d.defineProperty,f=e.hasOwnProperty||d.hasOwnProperty,A=e.create||e.inherit||d.create;d=[p,q,t,z,j,k];var y=m("o","delete o."+d.join(";delete o.")),b=A(null),u={},h,l;for(h=0;h<d.length;h++)d[h]=["if(h.call(a,'","'))b.","=a.",";"].join(d[h]);l=m("h","return function(a,b){"+d.join("")+"}")(f);g.as=function(a){return new v(a)};g.from=function(a,
-b,c){a=A("function"==typeof a?a.prototype:a);return b?g(a,b,c):a};g.later=function(a){return new w(a)};g.defaults={};e.redefine=g;return e}(_||this,Function,Object);
+var _=this._=function(f,m,d){function n(a,r,c,d){if(!(c instanceof v))if(c instanceof w){var f=c._,h=g.call(c,p)?!!c[p]:!0,m=g.call(c,q)&&c[q],n=g.call(c,k)&&c[k],s;c[t]=function(){b[j]=f.call(s=this);b[p]=h;b[q]=m;b[k]=n;x(s,r,b);y(b);return s[r]}}else c=(u[j]=c,u);l(d||e.defaults||{},b);l(c,b);if(g.call(c,t)||g.call(c,z))delete b[k],delete b[j];x(a,r,b);y(b);delete u[j]}function v(a){l(a,this)}function w(a){this._="function"==typeof a?a:l(a,this)||a[j]}function e(a,b,c,d){if("string"==typeof b)n(a,
+b,c,d);else for(var e in b)g.call(b,e)&&n(a,e,b[e],c);return a}var p="configurable",q="enumerable",t="get",z="set",j="value",k="writable",x=f.defineProperty||d.defineProperty,g=f.hasOwnProperty||d.hasOwnProperty,A=f.create||f.inherit||d.create;d=[p,q,t,z,j,k];var y=m("o","delete o."+d.join(";delete o.")),b=A(null),u={},h,l;for(h=0;h<d.length;h++)d[h]=["if(h.call(a,'","'))b.","=a.",";"].join(d[h]);l=m("h","return function(a,b){"+d.join("")+"}")(g);e.as=function(a){return new v(a)};e.from=function(a,
+b,c){a=A("function"==typeof a?a.prototype:a);return b?e(a,b,c):a};e.later=function(a){return new w(a)};e.defaults={};"undefined"!==typeof module&&module.exports&&((module.exports=e).redefine=e);f.redefine=e;return f}(_||this,Function,Object);

HOWTO.md

@@ -100,3 +100,3 @@ redefine VS ES5
 #### Real World Example: An Emitter Class
-This a simplified `Emitter` class with completely memory safe logic.
+This a simplified `Emitter` class with a logic optimized to save some memory and GC cycle.
 
@@ -152,4 +152,7 @@ // generic basic Emitter constructor
 
-Long story short: we can create 100 instances of `Emitter` and the amount of objects will be exactly `100 + 2` included the `Emitter` function and its prototype. Only when used, the `_handlers` object is created once and set as property to avoid calling the getter per each access. When listeners are removed, both Array used as type list and `_handlers` are removed, if empty. In order to obtain the same behavior in ES5:
+Long story short: we can create 100 instances of `Emitter` and the amount of extra objects will be exactly `100` instead of `200` considering a handler created during initialization.
 
+With this pattern, only when the `_handlers` object is needed is created once per instance and set as property to avoid calling the getter per each access.
+When listeners are removed, both Array used as type list and `_handlers` are removed, if empty. In order to obtain the same behavior in ES5:
+
     // ES5
@@ -209,13 +212,95 @@ Object.defineProperties(
 
+#### Real World Example: A Safer Definition
+While `Object.defineProperties(object, descriptorsList)` second argument loops only through `hasOwnProperty(key)`, once it comes to property definition, and the same is for `Object.defineProperty(obj, key, descriptor)`, the object used to described the property looks up for inherited properties too and consider them.
 
+Even if defaults are `{writable: false, enumerable: false, configurable: false}`, it's easy to make every property `enumerable` and `configurable` simply doing this:
 
+    Object.prototype.configurable = true;
+    Object.prototype.enumerable = true;
 
+After above malicious piece of code, if you think a constant variable defined like this cannot be changed you are wrong:
 
+    Object.defineProperty(window, "myLibrary", {value:myLibrary});
 
+It is necessary indeed to ensure that defaults are written as well, making defaults meaningless because of inheritance, but even worse, if a malicious code will write `Object.prototype.writable = true` and there are getters or setters involved, these will all throw an exception because `writable` does not accept getters or setters.
 
+##### How To Prevent Problems in ES5
+In ES5 every descriptor should inherit from `null` otherwise no descriptor will be immune from possible attacks.
 
+Here an example of few problems we might want to avoid:
 
+    // set up the nasty environment
+    Object.prototype.configurable =
+    Object.prototype.enumerable =
+    Object.prototype.writable = true;
+    
+    // verify that there are actually problems
+    try {
+      Object.defineProperty(this, "problem", {get: function () {
+        return "we gonna have bad time";
+      }});
+    } catch(o_O) {
+      console.log("ouch!");
+      Object.defineProperty(this, "problem", {value:true});
+      console.log(this.propertyIsEnumerable("problem")); // true
+      this.problem = {}; // no problems
+      delete this.problem; // true again
+    }
 
+Accordingly, every single descriptor should be created via `Object.crete(null)` so our code should look like
 
+    function descriptor(object) {
+      // now don't take this wrong
+      // but this function is almost
+      // as big as the whole redefine.js library
+      // I would not go through this pattern
+      for (var
+        nullDescriptor = Object.create(null),
+        properties = [
+          "configurable",
+          "enumerable",
+          "writable",
+          "get",
+          "set",
+          "value"
+        ],
+        i = properties.length; i--;
+        object.hasOwnProperty(properties[i]) && (
+          nullDescriptor[properties[i]] = object[properties[i]]
+        )
+      );
+      return nullDescriptor;
+    }
+    
+    Object.defineProperty(this, "problem", descriptor({
+      value: "now we talk"
+    }));
+    
+    this.propertyIsEnumerable("problem"); // false
+    this.problem = {}; // nope
+    delete this.problem; // false
+    this.problem; // "now we talk"
 
+Got it? Now ...
 
+##### How To Prevent Problems in redefine.js
+
+    redefine(this, "problem", "solved");
+    
+    this.propertyIsEnumerable("problem"); // false
+    this.problem = {}; // nope
+    delete this.problem; // false
+    this.problem; // "solved"
+
+If you are wondering about **performance** there are many things to consider behind `redefine.js` and one of these is that performance are really good for what it offers.
+
+While is usually slightly slower on desktop, `redefine.js` is [almost as fast in older Android 2.3 devices](http://jsperf.com/redefine-js) where performance matters the most.
+
+`redefine.js` is indeed suitable for mobile phones, even if quite old!
+
+
+
+
+
+
+

package.json

 {
   "name": "redefine",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "description": "A lightweight utility for an easier ES5 aware object properties definition introducing new, performance oriented, patterns.",
@@ -5,0 +5,0 @@ "homepage": "https://github.com/WebReflection/redefine",

src/redefine.js

@@ -173,2 +173,7 @@ var _ = this._ = function(_, Function, Object) {
 
+  // var redefine = require("redefine");
+  if ("undefined" !== typeof module && module.exports) {
+    (module.exports = redefine).redefine = redefine;
+  }
+
   // there you are ...
@@ -175,0 +180,0 @@ _.redefine = redefine;

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Improved metrics

Total package byte prevSize

50302

increased by8.4%

Lines of code

508

increased by0.79%

No dependency changes