{"id":152,"date":"2022-08-19T10:24:08","date_gmt":"2022-08-19T02:24:08","guid":{"rendered":"http:\/\/weboob.top\/blog\/?p=152"},"modified":"2022-08-19T10:24:08","modified_gmt":"2022-08-19T02:24:08","slug":"javascript%e4%b8%ad%e7%9a%84prototype%ef%bc%88%e5%8e%9f%e5%9e%8b%ef%bc%89","status":"publish","type":"post","link":"http:\/\/blog.weboob.top\/?p=152","title":{"rendered":"Javascript\u4e2d\u7684prototype\uff08\u539f\u578b\uff09"},"content":{"rendered":"\n

\u53c2\u8003\u6587\u732e<\/a><\/p>\n\n\n\n

\u6bcf\u4e00\u4e2a\u51fd\u6570\u90fd\u6709\u4e00\u4e2a prototype<\/code> \u5c5e\u6027\uff0c\u8fd9\u4e2a\u5c5e\u6027\u662f\u6307\u5411\u4e00\u4e2a\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u79f0\u4e3a \u539f\u578b\u5bf9\u8c61<\/code>\uff0c\u539f\u578b\u5bf9\u8c61<\/code>\u4e2d\u7684\u5c5e\u6027\u548c\u65b9\u6cd5\uff0c\u53ef\u4ee5\u88ab\u51fd\u6570 \u5b9e\u4f8b<\/code> \u6240\u7ee7\u627f\u548c\u5171\u4eab\u3002<\/p>\n\n\n\n

\u4e00\u3001\u79c1\u6709\u53d8\u91cf\u3001\u51fd\u6570<\/h3>\n\n\n\n

JavaScript\u4e2d\u6ca1\u6709\u547d\u540d\u7a7a\u95f4\u7684\u6982\u5ff5\uff0c\u540c\u65f6JavaScript\u652f\u6301\u51fd\u6570\u5d4c\u5957\u5b9a\u4e49\u3002\u4f46\u662f\uff0c\u5982\u679c\u51fd\u6570\u5185\u90e8\u5b9a\u4e49\u7684\u53d8\u91cf\u6216\u51fd\u6570\u4e0d\u5bf9\u5916\u63d0\u4f9b\u63a5\u53e3\uff0c\u90a3\u4e48\u5916\u90e8\u5c06\u65e0\u6cd5\u8bbf\u95ee<\/p>\n\n\n\n

\/**\n * obj\u4e2d\u7684\u53d8\u91cf\u548c\u51fd\u6570\u90fd\u662f\u79c1\u6709\u7684\uff0c\u5916\u90e8\u65e0\u6cd5\u8bbf\u95ee\n *\/<\/em>\nfunction obj(params) {\n    var a = 0;  \/\/ \u79c1\u6709\u53d8\u91cf<\/em>\n    var fn = function(){};  \/\/ \u79c1\u6709\u65b9\u6cd5<\/em>\n}\n\nvar o = new obj();\nconsole.log(o.a);   \/\/ undefined<\/em>\nconsole.log(o.fn);   \/\/ undefined<\/em>\n<\/code><\/pre>\n\n\n\n
\u4e8c\u3001\u9759\u6001\u53d8\u91cf\u548c\u51fd\u6570<\/h3>\n\n\n\n
\u901a\u8fc7 .<\/code> \u64cd\u4f5c\u7b26\uff0c\u6dfb\u52a0\u7684\u51fd\u6570\u6216\u53d8\u91cf\uff0c\u53ef\u4ee5\u901a\u8fc7\u5bf9\u8c61\u672c\u8eab\u8bbf\u95ee\u5230\uff0c\u4f46\u662f\u5176\u5b9e\u4f8b\u5bf9\u8c61\uff0c\u4ecd\u7136\u8bbf\u95ee\u4e0d\u5230\u3002\uff08\u7528\u8fc7java\u7684\u540c\u5b66\u5f88\u597d\u7406\u89e3\uff09<\/p>\n\n\n\n
\/**\n * \u5bf9\u8c61\u53ef\u4ee5\u8bbf\u95ee\n *\/<\/em>\nfunction obj(){}\n\nobj.a = 0;  \/\/ \u9759\u6001\u53d8\u91cf<\/em>\nobj.fn = function(){};  \/\/ \u9759\u6001\u65b9\u6cd5<\/em>\n\nconsole.log(a);     \/\/ 0<\/em>\nconsole.log(typeof obj.fn); \/\/ function<\/em>\n\n\/**\n * \u5b9e\u4f8b\u4e0d\u80fd\u8bbf\u95ee\n *\/<\/em>\nvar vm = new obj();\nconsole.log(vm.a);  \/\/ undefined<\/em>\nconsole.log(typeof vm.fn); \/\/ undefined<\/em>\n<\/code><\/pre>\n\n\n\n
\u4e09\u3001\u5b9e\u4f8b\u53d8\u91cf\u548c\u51fd\u6570<\/h3>\n\n\n\n
\u5728\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b\u7684\u6982\u5ff5\u4e2d\uff0c\u6211\u4eec\u8fd8\u662f\u9700\u8981\u5728\u5bf9\u8c61\u5728\u5b9a\u4e49\u7684\u65f6\u5019\u80fd\u540c\u65f6\u5b9a\u4e49\u4e00\u4e9b\u5c5e\u6027\u548c\u65b9\u6cd5\uff0c\u5b9e\u4f8b\u5316\u4e4b\u540e\uff0c\u53ef\u4ee5\u8bbf\u95ee\u3002<\/p>\n\n\n\n
\/**\n * \u5bf9\u8c61\u8bbf\u95ee\u4e0d\u5230\n *\/<\/em>\nfunction obj (){\n    this.a = [];    \/\/ \u5b9e\u4f8b\u53d8\u91cf<\/em>\n    this.fn = function(){}; \/\/ \u5b9e\u4f8b\u65b9\u6cd5<\/em>\n}\n\nconsole.log(typeof obj.a);  \/\/undefined<\/em>\nconsole.log(typeof obj.fn);     \/\/ undefined<\/em>\n\n\/**\n * \u5bf9\u8c61\u5b9e\u4f8b\u53ef\u4ee5\u8bbf\u95ee\u5230\n *\/<\/em>\nvar vm = new obj();\n\nconsole.log(typeof vm.a)\uff1b \/\/ object<\/em>\nconsole.log(typeof vm.fn);  \/\/ function<\/em>\n<\/code><\/pre>\n\n\n\n
\u7136\u800c\u4f1a\u9047\u5230\u5982\u4e0b\u95ee\u9898\uff1a<\/p>\n\n\n\n
\/**\n * \u5b9e\u4f8b\u5c5e\u6027\u4e0d\u4e00\u6837\n *\/<\/em>\nfunction obj (){\n    this.a = [];    \/\/ \u5b9e\u4f8b\u53d8\u91cf<\/em>\n    this.fn = function(){};  \/\/ \u5b9e\u4f8b\u65b9\u6cd5<\/em>\n}\n\nvar vm1 = new obj();\nvar vm2 = new obj();\n\nvm1.a.push(1);\nvm1.fn = {};\nconsole.log(vm1.a); \/\/ [1]<\/em>\nconsole.log(typeof vm1.fn); \/\/ object<\/em>\nconsole.log(vm2.a); \/\/ []<\/em>\nconsole.log(typeof vm2.fn); \/\/ function<\/em>\n<\/code><\/pre>\n\n\n\n
\u4ece\u4ee5\u4e0a\u4ee3\u7801\u53ef\u4ee5\u770b\u51fa\uff0c\u867d\u7136\u4e24\u4e2a\u5b9e\u4f8b\u5bf9\u8c61\u7684\u5c5e\u6027\u548c\u65b9\u6cd5\u540d\u79f0\u662f\u4e00\u6837\u7684\uff08\u7ee7\u627f\u81ea\u51fd\u6570\u5bf9\u8c61\uff09\uff0c\u4f46\u662f\u662f\u4e00\u4e2a\u590d\u5236\u3002\u5bf9\u4e8e\u5c5e\u6027\u6765\u8bf4\u6211\u4eec\u53ef\u4ee5\u63a5\u53d7\u3002\u4f46\u662f\u5bf9\u4e8e\u65b9\u6cd5\u6765\u8bf4\uff0c\u6ca1\u6709\u5fc5\u8981\uff08\u5982\u679c\u5b9a\u4e4910000\u4e2a\u5b9e\u4f8b\uff0c\u5c31\u670910000\u4e2acopy\uff09\u3002<\/p>\n\n\n\n
\u56db\u3001prototype<\/h3>\n\n\n\n
\u65e0\u8bba\u4ec0\u4e48\u65f6\u5019\uff0c\u53ea\u8981\u521b\u5efa\u4e86\u4e00\u4e2a\u51fd\u6570\uff0c\u5c31\u6709\u6839\u636e\u4e00\u7ec4\u7279\u5b9a\u7684\u89c4\u5219\uff0c\u4e3a\u8be5\u51fd\u6570\u521b\u9020\u4e00\u4e2aprototype<\/code>\u5c5e\u6027\u3002<\/p>\n\n\n\n
\u8be5\u5c5e\u6027\u6307\u5411\u4e00\u4e2a\u5bf9\u8c61\uff0c\u79f0\u4e3a \u539f\u578b\u5bf9\u8c61<\/code>\u3002\u8fd9\u4e2a\u5c5e\u6027\u4f1a\u5305\u542b\u4e00\u4e2aconstructor<\/code>\u6307\u9488\uff0c\u6307\u5411\u51fd\u6570\u539f\u578b\u3002<\/p>\n\n\n\n
\/**\n * \u51fd\u6570\u539f\u578b-\u9996\u5b57\u6bcd\u5927\u5199\n *\/<\/em>\nfunction Person(){}\n<\/code><\/pre>\n\n\n\n
\"20220818221645-2022-08-18-22-16-45\"\/<\/figure>\n\n\n\n
\u901a\u8fc7\u56fe\u7247\u53ef\u4ee5\u66f4\u597d\u7684\u7406\u89e3\u4ee5\u4e0a\u5185\u5bb9\u3002<\/p>\n\n\n\n
\u5f53\u8c03\u7528\u6784\u9020\u51fd\u6570\u521b\u5efa\u4e00\u4e2a\u5b9e\u4f8b\u65f6\uff0c\u5b9e\u4f8b\u5185\u90e8\u4f1a\u5305\u542b\u4e00\u4e2a\u5185\u90e8\u6307\u9488__proto__<\/code>\uff0c\u79f0\u4e3a\u9690\u5f0f\u539f\u578b\uff0c\u5b83\u6307\u5411\u6784\u9020\u51fd\u6570\u7684prototype<\/code>\u5bf9\u8c61\u3002<\/p>\n\n\n\n
\/**\n * \u5b9e\u4f8b\u548c\u51fd\u6570\u539f\u578b\n *\/<\/em>\nfunction Person(name){\n    this.name = name;   \/\/ \u5b9e\u4f8b\u5c5e\u6027<\/em>\n}\nPerson.prototype.printName = function(){\n    alert(this.name);\n}\n\nvar person1 = new Person('Byron');\nvar person2 = new Person('Frank');\n<\/code><\/pre>\n\n\n\n
\"20220818222415-2022-08-18-22-24-15\"\/<\/figure>\n\n\n\n
\u901a\u8fc7\u56fe\u7247\u53ef\u4ee5\u770b\u51fa\uff0cperson1\u4e2d\u5305\u542b\u4e86name\uff0c\u540c\u65f6\u4f1a\u6709 __proto__<\/code> -> Persion.prototype<\/code> (\u80fd\u770b\u5230printName)\uff0c\u5982\u4e0b\u56fe\u6240\u793a<\/p>\n\n\n\n
\"20220818222714-2022-08-18-22-27-14\"\/<\/figure>\n\n\n\n
\/**\n * prototype\u5185\u5bb9\u5171\u4eab\u6d4b\u8bd5\n *\/<\/em>\nfunction Person(name){\n    this.name = name;\n}\n\nPerson.prototype.share = [];\nPerson.prototype.printName = function(){ alert(this.name); };\n\nvar person1 = new Person('Byron');\nvar person2 = new Person('Frank');\n\nperson1.share.push(1);\nperson2.share.push(2);\nconsole.log(person2.share); \/\/ [1,2]<\/em>\n<\/code><\/pre>\n\n\n\n
\u5f53\u4ece\u5b9e\u4f8b\u4e2d\u83b7\u53d6\u5c5e\u6027\u65f6\uff0c\u4f1a\u5148\u67e5\u627e\u8be5\u5b9e\u4f8b\u662f\u5426\u5305\u542b\u3002\u5982\u679c\u6ca1\u6709\u5219\u67e5\u627e__proto__<\/code> \u6307\u5411\u7684prototype<\/code> \u91cc\u9762\u662f\u5426\u542b\u6709\uff0c\u6ca1\u6709\u5c31\u7ee7\u7eed\u9012\u5f52\u67e5\u627e\u3002\u76f4\u5230 Object.prototype<\/code>\uff0c\u4ecd\u7136\u6ca1\u6709\u5219\u62a5\u9519\u3002<\/p>\n\n\n\n
prototype\u4e2d\u7684\u5c5e\u6027\u53ef\u4ee5\u901a\u8fc7\u5b9e\u4f8b\u5c5e\u6027\u53bb\u8986\u76d6<\/p>\n\n\n\n
\/**\n * \u8986\u76d6prototype\u4e2d\u7684\u5c5e\u6027\n *\/<\/em>\nfunction Person(name){\n    this.name = name;\n}\nPerson.prototype.share = [];\n\nvar person = new Person('Byron');\nperson.share = 0;\nconsole.log(person.share); \/\/ 0 \u4e0d\u662f []<\/em>\n<\/code><\/pre>\n\n\n\n
\u4e94\u3001\u603b\u7ed3<\/h3>\n\n\n\n
\u5982\u679c\u5e0c\u671b\u5b9e\u4f8b\u590d\u7528\u5bf9\u8c61\u7684\u5c5e\u6027\u6216\u51fd\u6570\uff0c\u5219\u653e\u5230 prototype<\/code> \u4e2d\u3002 \u5982\u679c\u5e0c\u671b\u6bcf\u4e2a\u5b9e\u4f8b\u5355\u72ec\u62e5\u6709\u7684\u5c5e\u6027\u548c\u65b9\u6cd5\uff0c\u5219\u5b9a\u4e49\u5230this\u4e2d\uff0c\u901a\u8fc7\u6784\u9020\u51fd\u6570\u4f20\u9012\u5b9e\u4f8b\u5316\u53c2\u6570\u3002<\/p>\n\n\n\n
function Person(name){\n    this.name = name;\n}\n\nPerson.prototype.share = [];\nPerson.prototype.printName = function(){\n    alert(this.name);\n}\n<\/code><\/pre>\n\n\n\n
\u516d\u3001\u539f\u578b\u94fe\u793a\u610f\u56fe<\/h3>\n\n\n\n
\u5047\u8bbe\u6709\u4e2aPerson<\/p>\n\n\n\n
function Person(){}\nnew Person();\n<\/code><\/pre>\n\n\n\n
\u6b64\u65f6\uff0c\u4f1a\u6709\u5982\u4e0b\u5173\u7cfb\uff1a<\/p>\n\n\n\n
  • \u7ea2\u8272\uff1afunction Person(){}<\/li>
  • \u84dd\u8272\uff1aPerson.prototype<\/li>
  • \u7eff\u8272: new Person()<\/li>
  • prototype\u548c__proto__(\u4e00\u822c\u6d4f\u89c8\u5668\u90fd\u53eb\u8fd9\u4e2a)\u662f\u81ea\u52a8\u751f\u6210<\/li><\/ul>\n\n\n\n
    \u4ee5\u4e0b\u56fe\u7247\u4e2d\u7ebf\u6761<\/p>\n\n\n\n
    • \u84dd\u8272\uff1aprototype<\/li>
    • \u7eff\u8272\uff1anew<\/li>
    • \u9ed1\u8272\uff1aproto<\/strong><\/li><\/ul>\n\n\n\n
      \"20220819090953-2022-08-19-09-09-53\"\/<\/figure>\n\n\n\n
      \u800c\u5176\u4e2dPerson\u51fd\u6570\uff0c\u53c8\u662f new Function()<\/code>\u751f\u6210\u7684\u5b9e\u4f8b\uff0c\u6240\u4ee5\u5173\u7cfb\u56fe\u5982\u4e0b\uff1a<\/p>\n\n\n\n
      \"20220819092506-2022-08-19-09-25-06\"\/<\/figure>\n\n\n\n
      Person.prototype = {}<\/code> \u4ed6\u662f\u4e2aObject \u5b9e\u4f8b\uff0c\u76f8\u5f53\u4e8e new Object();<\/code>\uff0c\u6240\u4ee5\u53c8\u6709\u5982\u4e0b\u5173\u7cfb\u56fe\uff1a<\/p>\n\n\n\n
      \"20220819094705-2022-08-19-09-47-05\"\/<\/figure>\n\n\n\n
      \u540c\u7406 Function.prototype<\/code> \u4e5f\u662f\u5982\u6b64\uff0c\u6240\u4ee5\u5173\u7cfb\u56fe\u5982\u4e0b\uff1a<\/p>\n\n\n\n
      \"20220819095320-2022-08-19-09-53-20\"\/<\/figure>\n\n\n\n
      \u5173\u7cfb\u56fe\u4e2d Object.prototype<\/code> \u6bd4\u8f83\u7279\u6b8a\uff0c\u5b83\u7684\u9690\u5f0f\u539f\u578b\u4e3anull<\/code>\u3002
      Object()<\/code> \u51fd\u6570\u4e3anew Function()<\/code>\uff0c\u6240\u4ee5\u5b83\u662f\u5176\u5b9e\u4f8b\uff0c\u540c\u65f6\u5176\u9690\u5f0f\u539f\u578b\u4e3aFunction.prototype<\/code>\u3002
      \u6700\u540e\u4e00\u70b9\u662fFunction()<\/code>\u51fd\u6570\u7684\u9690\u5f0f\u539f\u578b\u6307\u5411Function.prototype<\/code><\/p>\n\n\n\n
      \u6240\u4ee5\u6700\u7ec8\u5173\u7cfb\u56fe\u5982\u4e0b\uff1a<\/p>\n\n\n\n
      \"20220819101128-2022-08-19-10-11-28\"\/<\/figure>\n\n\n\n
      \u5f53\u6211\u4eec\u53bb\u7528\u5b9e\u4f8b\u53bb\u8c03\u7528\u5c5e\u6027\u6216\u65b9\u6cd5\u65f6<\/p>\n\n\n\n
      person1.toString();\n<\/code><\/pre>\n\n\n\n
      \u67e5\u627e\u987a\u5e8f\u4e3a(\u6cbf\u6700\u5de6\u4fa7\u9ed1\u8272\u7bad\u5934)\uff1aperson1\u81ea\u8eab\u5c5e\u6027<\/code> -> Person.prototype<\/code> -> Object.prototype<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"
      \u53c2\u8003\u6587\u732e \u6bcf\u4e00\u4e2a\u51fd\u6570\u90fd\u6709\u4e00\u4e2a prototype \u5c5e\u6027\uff0c\u8fd9\u4e2a\u5c5e\u6027\u662f\u6307\u5411\u4e00\u4e2a\u5bf9\u8c61\u7684\u5f15\u7528\uff0c\u79f0\u4e3a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[23,25,27],"class_list":["post-152","post","type-post","status-publish","format-standard","hentry","category-js","tag-js","tag-prototype","tag-27"],"_links":{"self":[{"href":"http:\/\/blog.weboob.top\/index.php?rest_route=\/wp\/v2\/posts\/152","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/blog.weboob.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blog.weboob.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blog.weboob.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/blog.weboob.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=152"}],"version-history":[{"count":0,"href":"http:\/\/blog.weboob.top\/index.php?rest_route=\/wp\/v2\/posts\/152\/revisions"}],"wp:attachment":[{"href":"http:\/\/blog.weboob.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=152"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blog.weboob.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=152"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blog.weboob.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=152"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}