Created
July 4, 2013 17:49
-
-
Save teramako/5929337 to your computer and use it in GitHub Desktop.
__proto__ のテスト
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>__proto__ test</title> | |
| </head> | |
| <body> | |
| <h1>__proto__ test</h1> | |
| <div id="out"></div> | |
| <script> | |
| var $out = document.getElementById("out"); | |
| function print(msg){ | |
| out.insertAdjacentHTML("BeforeEnd", msg); | |
| } | |
| // 1 | |
| var desc = Object.getOwnPropertyDescriptor(Object.prototype, "__proto__"); | |
| var props = Object.getOwnPropertyNames(desc); | |
| print( | |
| "<h2>Descriptor</h2>" + | |
| "<dl>" + | |
| props.map(function (key) { | |
| return "<dt>" + key + "</dt><dd>" + desc[key] + "</dd>" | |
| }).join("") + | |
| "</dl>" | |
| ); | |
| var proto = { | |
| getName: function (){ return "PROTO"; } | |
| }; | |
| var obj = { | |
| __proto__: proto | |
| }; | |
| print("<h2>var obj = { __proto__: proto }</h2>"); | |
| print("<p>obj.__proto__ is proto: " + (Object.getPrototypeOf(obj) === proto) + "</p>"); | |
| var obj2 = Object.create(null); | |
| print("<h2>var obj2 = Object.create(null)<h2>"); | |
| print("<p>__proto__ in obj2: " + ("__proto__" in obj2) + "</p>"); | |
| obj2.__proto__ = "OK"; | |
| print("<p>obj2 hasOwn '__proto__': " + Object.prototype.hasOwnProperty.call(obj2, "__proto__") + "</p>"); | |
| print("<p>JSON.stringify(obj2): " + JSON.stringify(obj2) + "</p>"); | |
| var obj3 = JSON.parse('{ "__proto__": "PROTO" }'); | |
| print("<h2>var obj3 = JSON.parse('{ \"__proto__\": \"PROTO\" }')</h2>"); | |
| print("<p>obj3's keys: " + Object.keys(obj3) + "</p>"); | |
| print("<p>JSON.stringify(obj3): " + JSON.stringify(obj3) + "</p>"); | |
| </script> | |
| </body> | |
| </html> |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment