{"id":1357,"date":"2024-06-02T22:21:51","date_gmt":"2024-06-02T22:21:51","guid":{"rendered":""},"modified":"2024-06-05T03:08:19","modified_gmt":"2024-06-04T19:08:19","slug":"es6-%e7%b3%bb%e5%88%97%e4%b9%8b-defineproperty-%e4%b8%8e-proxy","status":"publish","type":"post","link":"https:\/\/www.lccc.top\/?p=1357","title":{"rendered":"ES6 \u7cfb\u5217\u4e4b defineProperty \u4e0e proxy"},"content":{"rendered":"\n

\u524d\u8a00<\/h2>\n

\u6211\u4eec\u6216\u591a\u6216\u5c11\u90fd\u542c\u8fc7\u201c\u6570\u636e\u7ed1\u5b9a\u201d\u8fd9\u4e2a\u8bcd\uff0c\u201c\u6570\u636e\u7ed1\u5b9a\u201d\u7684\u5173\u952e\u5728\u4e8e\u76d1\u542c\u6570\u636e\u7684\u53d8\u5316\uff0c\u53ef\u662f\u5bf9\u4e8e\u8fd9\u6837\u4e00\u4e2a\u5bf9\u8c61\uff1avar obj = {value: 1}<\/code>\uff0c\u6211\u4eec\u8be5\u600e\u4e48\u77e5\u9053 obj \u53d1\u751f\u4e86\u6539\u53d8\u5462\uff1f<\/p>\n

definePropety<\/h2>\n

ES5 \u63d0\u4f9b\u4e86 Object.defineProperty \u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u53ef\u4ee5\u5728\u4e00\u4e2a\u5bf9\u8c61\u4e0a\u5b9a\u4e49\u4e00\u4e2a\u65b0\u5c5e\u6027\uff0c\u6216\u8005\u4fee\u6539\u4e00\u4e2a\u5bf9\u8c61\u7684\u73b0\u6709\u5c5e\u6027\uff0c\u5e76\u8fd4\u56de\u8fd9\u4e2a\u5bf9\u8c61\u3002<\/p>\n

\u8bed\u6cd5<\/strong><\/p>\n

\n

Object.defineProperty(obj, prop, descriptor)<\/p>\n<\/blockquote>\n

\u53c2\u6570<\/strong><\/p>\n

<\/p>\n
obj: \u8981\u5728\u5176\u4e0a\u5b9a\u4e49\u5c5e\u6027\u7684\u5bf9\u8c61\u3002\n\nprop:  \u8981\u5b9a\u4e49\u6216\u4fee\u6539\u7684\u5c5e\u6027\u7684\u540d\u79f0\u3002\n\ndescriptor: \u5c06\u88ab\u5b9a\u4e49\u6216\u4fee\u6539\u7684\u5c5e\u6027\u7684\u63cf\u8ff0\u7b26\u3002\n<\/code><\/pre>\n<\/div>\n
\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
<\/p>\n
var<\/span> obj<\/span> =<\/span> {<\/span>}<\/span>;<\/span>\nObject<\/span>.<\/span>defineProperty<\/span>(<\/span>obj<\/span>,<\/span> \"num\"<\/span>,<\/span> {<\/span>\n    value<\/span> : 1<\/span>,<\/span>\n    writable<\/span> : true<\/span>,<\/span>\n    enumerable<\/span> : true<\/span>,<\/span>\n    configurable<\/span> : true<\/span>\n}<\/span>)<\/span>;<\/span>\n\/\/  \u5bf9\u8c61 obj \u62e5\u6709\u5c5e\u6027 num\uff0c\u503c\u4e3a 1<\/span><\/pre>\n<\/div>\n
\u867d\u7136\u6211\u4eec\u53ef\u4ee5\u76f4\u63a5\u6dfb\u52a0\u5c5e\u6027\u548c\u503c\uff0c\u4f46\u662f\u4f7f\u7528\u8fd9\u79cd\u65b9\u5f0f\uff0c\u6211\u4eec\u80fd\u8fdb\u884c\u66f4\u591a\u7684\u914d\u7f6e\u3002<\/p>\n
\u51fd\u6570\u7684\u7b2c\u4e09\u4e2a\u53c2\u6570 descriptor \u6240\u8868\u793a\u7684\u5c5e\u6027\u63cf\u8ff0\u7b26\u6709\u4e24\u79cd\u5f62\u5f0f\uff1a\u6570\u636e\u63cf\u8ff0\u7b26\u548c\u5b58\u53d6\u63cf\u8ff0\u7b26<\/strong>\u3002<\/p>\n
\u4e24\u8005\u5747\u5177\u6709\u4ee5\u4e0b\u4e24\u79cd\u952e\u503c<\/strong>\uff1a<\/p>\n
configurable<\/strong><\/p>\n
\n
\u5f53\u4e14\u4ec5\u5f53\u8be5\u5c5e\u6027\u7684 configurable \u4e3a true \u65f6\uff0c\u8be5\u5c5e\u6027\u63cf\u8ff0\u7b26\u624d\u80fd\u591f\u88ab\u6539\u53d8\uff0c\u4e5f\u80fd\u591f\u88ab\u5220\u9664\u3002\u9ed8\u8ba4\u4e3a false\u3002\n<\/code><\/pre>\n<\/div>\n
enumerable<\/strong><\/p>\n
\n
\u5f53\u4e14\u4ec5\u5f53\u8be5\u5c5e\u6027\u7684 enumerable \u4e3a true \u65f6\uff0c\u8be5\u5c5e\u6027\u624d\u80fd\u591f\u51fa\u73b0\u5728\u5bf9\u8c61\u7684\u679a\u4e3e\u5c5e\u6027\u4e2d\u3002\u9ed8\u8ba4\u4e3a false\u3002\n<\/code><\/pre>\n<\/div>\n
\u6570\u636e\u63cf\u8ff0\u7b26\u540c\u65f6\u5177\u6709\u4ee5\u4e0b\u53ef\u9009\u952e\u503c<\/strong>\uff1a<\/p>\n
value<\/strong><\/p>\n
\n
\u8be5\u5c5e\u6027\u5bf9\u5e94\u7684\u503c\u3002\u53ef\u4ee5\u662f\u4efb\u4f55\u6709\u6548\u7684 JavaScript \u503c\uff08\u6570\u503c\uff0c\u5bf9\u8c61\uff0c\u51fd\u6570\u7b49\uff09\u3002\u9ed8\u8ba4\u4e3a undefined\u3002\n<\/code><\/pre>\n<\/div>\n
writable<\/strong><\/p>\n
\n
\u5f53\u4e14\u4ec5\u5f53\u8be5\u5c5e\u6027\u7684 writable \u4e3a true \u65f6\uff0c\u8be5\u5c5e\u6027\u624d\u80fd\u88ab\u8d4b\u503c\u8fd0\u7b97\u7b26\u6539\u53d8\u3002\u9ed8\u8ba4\u4e3a false\u3002\n<\/code><\/pre>\n<\/div>\n
\u5b58\u53d6\u63cf\u8ff0\u7b26\u540c\u65f6\u5177\u6709\u4ee5\u4e0b\u53ef\u9009\u952e\u503c<\/strong>\uff1a<\/p>\n
get<\/strong><\/p>\n
\n
\u4e00\u4e2a\u7ed9\u5c5e\u6027\u63d0\u4f9b getter \u7684\u65b9\u6cd5\uff0c\u5982\u679c\u6ca1\u6709 getter \u5219\u4e3a undefined\u3002\u8be5\u65b9\u6cd5\u8fd4\u56de\u503c\u88ab\u7528\u4f5c\u5c5e\u6027\u503c\u3002\u9ed8\u8ba4\u4e3a undefined\u3002\n<\/code><\/pre>\n<\/div>\n
set<\/strong><\/p>\n
\n
\u4e00\u4e2a\u7ed9\u5c5e\u6027\u63d0\u4f9b setter \u7684\u65b9\u6cd5\uff0c\u5982\u679c\u6ca1\u6709 setter \u5219\u4e3a undefined\u3002\u8be5\u65b9\u6cd5\u5c06\u63a5\u53d7\u552f\u4e00\u53c2\u6570\uff0c\u5e76\u5c06\u8be5\u53c2\u6570\u7684\u65b0\u503c\u5206\u914d\u7ed9\u8be5\u5c5e\u6027\u3002\u9ed8\u8ba4\u4e3a undefined\u3002\n<\/code><\/pre>\n<\/div>\n
\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff1a<\/p>\n
\u5c5e\u6027\u63cf\u8ff0\u7b26\u5fc5\u987b\u662f\u6570\u636e\u63cf\u8ff0\u7b26\u6216\u8005\u5b58\u53d6\u63cf\u8ff0\u7b26\u4e24\u79cd\u5f62\u5f0f\u4e4b\u4e00\uff0c\u4e0d\u80fd\u540c\u65f6\u662f\u4e24\u8005<\/strong> \u3002\u8fd9\u5c31\u610f\u5473\u7740\u4f60\u53ef\u4ee5\uff1a<\/p>\n
<\/p>\n
Object<\/span>.<\/span>defineProperty<\/span>(<\/span>{<\/span>}<\/span>,<\/span> \"num\"<\/span>,<\/span> {<\/span>\n    value<\/span>: 1<\/span>,<\/span>\n    writable<\/span>: true<\/span>,<\/span>\n    enumerable<\/span>: true<\/span>,<\/span>\n    configurable<\/span>: true<\/span>\n}<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u4e5f\u53ef\u4ee5\uff1a<\/p>\n
<\/p>\n
var<\/span> value<\/span> =<\/span> 1<\/span>;<\/span>\nObject<\/span>.<\/span>defineProperty<\/span>(<\/span>{<\/span>}<\/span>,<\/span> \"num\"<\/span>,<\/span> {<\/span>\n    get<\/span> : function<\/span>(<\/span>)<\/span>{<\/span>\n      return<\/span> value<\/span>;<\/span>\n    }<\/span>,<\/span>\n    set<\/span> : function<\/span>(<\/span>newValue<\/span>)<\/span>{<\/span>\n      value<\/span> =<\/span> newValue<\/span>;<\/span>\n    }<\/span>,<\/span>\n    enumerable<\/span> : true<\/span>,<\/span>\n    configurable<\/span> : true<\/span>\n}<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u4f46\u662f\u4e0d\u53ef\u4ee5\uff1a<\/p>\n
<\/p>\n
\/\/ \u62a5\u9519<\/span>\nObject<\/span>.<\/span>defineProperty<\/span>(<\/span>{<\/span>}<\/span>,<\/span> \"num\"<\/span>,<\/span> {<\/span>\n    value<\/span>: 1<\/span>,<\/span>\n    get<\/span>: function<\/span>(<\/span>)<\/span> {<\/span>\n        return<\/span> 1<\/span>;<\/span>\n    }<\/span>\n}<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u6b64\u5916\uff0c\u6240\u6709\u7684\u5c5e\u6027\u63cf\u8ff0\u7b26\u90fd\u662f\u975e\u5fc5\u987b\u7684\uff0c\u4f46\u662f descriptor \u8fd9\u4e2a\u5b57\u6bb5\u662f\u5fc5\u987b\u7684\uff0c\u5982\u679c\u4e0d\u8fdb\u884c\u4efb\u4f55\u914d\u7f6e\uff0c\u4f60\u53ef\u4ee5\u8fd9\u6837\uff1a<\/p>\n
<\/p>\n
var<\/span> obj<\/span> =<\/span> Object<\/span>.<\/span>defineProperty<\/span>(<\/span>{<\/span>}<\/span>,<\/span> \"num\"<\/span>,<\/span> {<\/span>}<\/span>)<\/span>;<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>obj<\/span>.<\/span>num<\/span>)<\/span>;<\/span> \/\/ undefined<\/span><\/pre>\n<\/div>\n
Setters \u548c Getters<\/h2>\n
\u4e4b\u6240\u4ee5\u8bb2\u5230 defineProperty\uff0c\u662f\u56e0\u4e3a\u6211\u4eec\u8981\u4f7f\u7528\u5b58\u53d6\u63cf\u8ff0\u7b26\u4e2d\u7684 get \u548c set\uff0c\u8fd9\u4e24\u4e2a\u65b9\u6cd5\u53c8\u88ab\u79f0\u4e3a getter \u548c setter\u3002\u7531 getter \u548c setter \u5b9a\u4e49\u7684\u5c5e\u6027\u79f0\u505a\u201d\u5b58\u53d6\u5668\u5c5e\u6027\u201c\u3002<\/p>\n
\u5f53\u7a0b\u5e8f\u67e5\u8be2\u5b58\u53d6\u5668\u5c5e\u6027\u7684\u503c\u65f6\uff0cJavaScript \u8c03\u7528 getter\u65b9\u6cd5\u3002\u8fd9\u4e2a\u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u5c31\u662f\u5c5e\u6027\u5b58\u53d6\u8868\u8fbe\u5f0f\u7684\u503c\u3002\u5f53\u7a0b\u5e8f\u8bbe\u7f6e\u4e00\u4e2a\u5b58\u53d6\u5668\u5c5e\u6027\u7684\u503c\u65f6\uff0cJavaScript \u8c03\u7528 setter \u65b9\u6cd5\uff0c\u5c06\u8d4b\u503c\u8868\u8fbe\u5f0f\u53f3\u4fa7\u7684\u503c\u5f53\u505a\u53c2\u6570\u4f20\u5165 setter\u3002\u4ece\u67d0\u79cd\u610f\u4e49\u4e0a\u8bb2\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u8d1f\u8d23\u201c\u8bbe\u7f6e\u201d\u5c5e\u6027\u503c\u3002\u53ef\u4ee5\u5ffd\u7565 setter \u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u3002<\/p>\n
\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
<\/p>\n
var<\/span> obj<\/span> =<\/span> {<\/span>}<\/span>,<\/span> value<\/span> =<\/span> null<\/span>;<\/span>\nObject<\/span>.<\/span>defineProperty<\/span>(<\/span>obj<\/span>,<\/span> \"num\"<\/span>,<\/span> {<\/span>\n    get<\/span>: function<\/span>(<\/span>)<\/span>{<\/span>\n        console<\/span>.<\/span>log<\/span>(<\/span>'\u6267\u884c\u4e86 get \u64cd\u4f5c'<\/span>)<\/span>\n        return<\/span> value<\/span>;<\/span>\n    }<\/span>,<\/span>\n    set<\/span>: function<\/span>(<\/span>newValue<\/span>)<\/span> {<\/span>\n        console<\/span>.<\/span>log<\/span>(<\/span>'\u6267\u884c\u4e86 set \u64cd\u4f5c'<\/span>)<\/span>\n        value<\/span> =<\/span> newValue<\/span>;<\/span>\n    }<\/span>\n}<\/span>)<\/span>\n\nobj<\/span>.<\/span>num<\/span> =<\/span> 1<\/span> \/\/ \u6267\u884c\u4e86 set \u64cd\u4f5c<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>obj<\/span>.<\/span>num<\/span>)<\/span>;<\/span> \/\/ \u6267\u884c\u4e86 get \u64cd\u4f5c \/\/ 1<\/span><\/pre>\n<\/div>\n
\u8fd9\u4e0d\u5c31\u662f\u6211\u4eec\u8981\u7684\u76d1\u63a7\u6570\u636e\u6539\u53d8\u7684\u65b9\u6cd5\u5417\uff1f\u6211\u4eec\u518d\u6765\u5c01\u88c5\u4e00\u4e0b\uff1a<\/p>\n
<\/p>\n
function<\/span> Archiver<\/span>(<\/span>)<\/span> {<\/span>\n    var<\/span> value<\/span> =<\/span> null<\/span>;<\/span>\n    \/\/ archive n. \u6863\u6848<\/span>\n    var<\/span> archive<\/span> =<\/span> [<\/span>]<\/span>;<\/span>\n\n    Object<\/span>.<\/span>defineProperty<\/span>(<\/span>this<\/span>,<\/span> 'num'<\/span>,<\/span> {<\/span>\n        get<\/span>: function<\/span>(<\/span>)<\/span> {<\/span>\n            console<\/span>.<\/span>log<\/span>(<\/span>'\u6267\u884c\u4e86 get \u64cd\u4f5c'<\/span>)<\/span>\n            return<\/span> value<\/span>;<\/span>\n        }<\/span>,<\/span>\n        set<\/span>: function<\/span>(<\/span>value<\/span>)<\/span> {<\/span>\n            console<\/span>.<\/span>log<\/span>(<\/span>'\u6267\u884c\u4e86 set \u64cd\u4f5c'<\/span>)<\/span>\n            value<\/span> =<\/span> value<\/span>;<\/span>\n            archive<\/span>.<\/span>push<\/span>(<\/span>{<\/span> val<\/span>: value<\/span> }<\/span>)<\/span>;<\/span>\n        }<\/span>\n    }<\/span>)<\/span>;<\/span>\n\n    this<\/span>.<\/span>getArchive<\/span> =<\/span> function<\/span>(<\/span>)<\/span> {<\/span> return<\/span> archive<\/span>;<\/span> }<\/span>;<\/span>\n}<\/span>\n\nvar<\/span> arc<\/span> =<\/span> new<\/span> Archiver<\/span>(<\/span>)<\/span>;<\/span>\narc<\/span>.<\/span>num<\/span>;<\/span> \/\/ \u6267\u884c\u4e86 get \u64cd\u4f5c<\/span>\narc<\/span>.<\/span>num<\/span> =<\/span> 11<\/span>;<\/span> \/\/ \u6267\u884c\u4e86 set \u64cd\u4f5c<\/span>\narc<\/span>.<\/span>num<\/span> =<\/span> 13<\/span>;<\/span> \/\/ \u6267\u884c\u4e86 set \u64cd\u4f5c<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>arc<\/span>.<\/span>getArchive<\/span>(<\/span>)<\/span>)<\/span>;<\/span> \/\/ [{ val: 11 }, { val: 13 }]<\/span><\/pre>\n<\/div>\n
watch API<\/h2>\n
\u65e2\u7136\u53ef\u4ee5\u76d1\u63a7\u6570\u636e\u7684\u6539\u53d8\uff0c\u90a3\u6211\u53ef\u4ee5\u8fd9\u6837\u8bbe\u60f3\uff0c\u5373\u5f53\u6570\u636e\u6539\u53d8\u7684\u65f6\u5019\uff0c\u81ea\u52a8\u8fdb\u884c\u6e32\u67d3\u5de5\u4f5c\u3002\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
HTML \u4e2d\u6709\u4e2a span \u6807\u7b7e\u548c button \u6807\u7b7e<\/p>\n
<\/p>\n
<<\/span>span<\/span> id<\/span>=\"container<\/span>\"><\/span>1<\/<\/span>span<\/span>><\/span>\n<<\/span>button<\/span> id<\/span>=\"button<\/span>\"><\/span>\u70b9\u51fb\u52a0 1<\/<\/span>button<\/span>><\/span><\/pre>\n<\/div>\n
\u5f53\u70b9\u51fb\u6309\u94ae\u7684\u65f6\u5019\uff0cspan \u6807\u7b7e\u91cc\u7684\u503c\u52a0 1\u3002<\/p>\n
\u4f20\u7edf\u7684\u505a\u6cd5\u662f\uff1a<\/p>\n
<\/p>\n
document<\/span>.<\/span>getElementById<\/span>(<\/span>'button'<\/span>)<\/span>.<\/span>addEventListener<\/span>(<\/span>\"click\"<\/span>,<\/span> function<\/span>(<\/span>)<\/span>{<\/span>\n    var<\/span> container<\/span> =<\/span> document<\/span>.<\/span>getElementById<\/span>(<\/span>\"container\"<\/span>)<\/span>;<\/span>\n    container<\/span>.<\/span>innerHTML<\/span> =<\/span> Number<\/span>(<\/span>container<\/span>.<\/span>innerHTML<\/span>)<\/span> +<\/span> 1<\/span>;<\/span>\n}<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u5982\u679c\u4f7f\u7528\u4e86 defineProperty\uff1a<\/p>\n
<\/p>\n
var<\/span> obj<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>\n}<\/span>\n\n\/\/ \u50a8\u5b58 obj.value \u7684\u503c<\/span>\nvar<\/span> value<\/span> =<\/span> 1<\/span>;<\/span>\n\nObject<\/span>.<\/span>defineProperty<\/span>(<\/span>obj<\/span>,<\/span> \"value\"<\/span>,<\/span> {<\/span>\n    get<\/span>: function<\/span>(<\/span>)<\/span> {<\/span>\n        return<\/span> value<\/span>;<\/span>\n    }<\/span>,<\/span>\n    set<\/span>: function<\/span>(<\/span>newValue<\/span>)<\/span> {<\/span>\n        value<\/span> =<\/span> newValue<\/span>;<\/span>\n        document<\/span>.<\/span>getElementById<\/span>(<\/span>'container'<\/span>)<\/span>.<\/span>innerHTML<\/span> =<\/span> newValue<\/span>;<\/span>\n    }<\/span>\n}<\/span>)<\/span>;<\/span>\n\ndocument<\/span>.<\/span>getElementById<\/span>(<\/span>'button'<\/span>)<\/span>.<\/span>addEventListener<\/span>(<\/span>\"click\"<\/span>,<\/span> function<\/span>(<\/span>)<\/span> {<\/span>\n    obj<\/span>.<\/span>value<\/span> +=<\/span> 1<\/span>;<\/span>\n}<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u4ee3\u7801\u770b\u4f3c\u589e\u591a\u4e86\uff0c\u4f46\u662f\u5f53\u6211\u4eec\u9700\u8981\u6539\u53d8 span \u6807\u7b7e\u91cc\u7684\u503c\u7684\u65f6\u5019\uff0c\u76f4\u63a5\u4fee\u6539 obj.value \u7684\u503c\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n
\u7136\u800c\uff0c\u73b0\u5728\u7684\u5199\u6cd5\uff0c\u6211\u4eec\u8fd8\u9700\u8981\u5355\u72ec\u58f0\u660e\u4e00\u4e2a\u53d8\u91cf\u5b58\u50a8 obj.value \u7684\u503c\uff0c\u56e0\u4e3a\u5982\u679c\u4f60\u5728 set \u4e2d\u76f4\u63a5 obj.value = newValue<\/code> \u5c31\u4f1a\u9677\u5165\u65e0\u9650\u7684\u5faa\u73af\u4e2d\u3002\u6b64\u5916\uff0c\u6211\u4eec\u53ef\u80fd\u9700\u8981\u76d1\u63a7\u5f88\u591a\u5c5e\u6027\u503c\u7684\u6539\u53d8\uff0c\u8981\u662f\u4e00\u4e2a\u4e00\u4e2a\u5199\uff0c\u4e5f\u5f88\u7d2f\u5450\uff0c\u6240\u4ee5\u6211\u4eec\u7b80\u5355\u5199\u4e2a watch \u51fd\u6570\u3002\u4f7f\u7528\u6548\u679c\u5982\u4e0b\uff1a<\/p>\n
<\/p>\n
var<\/span> obj<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>\n}<\/span>\n\nwatch<\/span>(<\/span>obj<\/span>,<\/span> \"value\"<\/span>,<\/span> function<\/span>(<\/span>newvalue<\/span>)<\/span>{<\/span>\n    document<\/span>.<\/span>getElementById<\/span>(<\/span>'container'<\/span>)<\/span>.<\/span>innerHTML<\/span> =<\/span> newvalue<\/span>;<\/span>\n}<\/span>)<\/span>\n\ndocument<\/span>.<\/span>getElementById<\/span>(<\/span>'button'<\/span>)<\/span>.<\/span>addEventListener<\/span>(<\/span>\"click\"<\/span>,<\/span> function<\/span>(<\/span>)<\/span>{<\/span>\n    obj<\/span>.<\/span>value<\/span> +=<\/span> 1<\/span>\n}<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u6211\u4eec\u6765\u5199\u4e0b\u8fd9\u4e2a watch \u51fd\u6570\uff1a<\/p>\n
<\/p>\n
(<\/span>function<\/span>(<\/span>)<\/span>{<\/span>\n    var<\/span> root<\/span> =<\/span> this<\/span>;<\/span>\n    function<\/span> watch<\/span>(<\/span>obj<\/span>,<\/span> name<\/span>,<\/span> func<\/span>)<\/span>{<\/span>\n        var<\/span> value<\/span> =<\/span> obj<\/span>[<\/span>name<\/span>]<\/span>;<\/span>\n\n        Object<\/span>.<\/span>defineProperty<\/span>(<\/span>obj<\/span>,<\/span> name<\/span>,<\/span> {<\/span>\n            get<\/span>: function<\/span>(<\/span>)<\/span> {<\/span>\n                return<\/span> value<\/span>;<\/span>\n            }<\/span>,<\/span>\n            set<\/span>: function<\/span>(<\/span>newValue<\/span>)<\/span> {<\/span>\n                value<\/span> =<\/span> newValue<\/span>;<\/span>\n                func<\/span>(<\/span>value<\/span>)<\/span>\n            }<\/span>\n        }<\/span>)<\/span>;<\/span>\n\n        if<\/span> (<\/span>value<\/span>)<\/span> obj<\/span>[<\/span>name<\/span>]<\/span> =<\/span> value<\/span>\n    }<\/span>\n\n    this<\/span>.<\/span>watch<\/span> =<\/span> watch<\/span>;<\/span>\n}<\/span>)<\/span>(<\/span>)<\/span><\/pre>\n<\/div>\n
\u73b0\u5728\u6211\u4eec\u5df2\u7ecf\u53ef\u4ee5\u76d1\u63a7\u5bf9\u8c61\u5c5e\u6027\u503c\u7684\u6539\u53d8\uff0c\u5e76\u4e14\u53ef\u4ee5\u6839\u636e\u5c5e\u6027\u503c\u7684\u6539\u53d8\uff0c\u6dfb\u52a0\u56de\u8c03\u51fd\u6570\uff0c\u68d2\u68d2\u54d2~<\/p>\n
proxy<\/h2>\n
\u4f7f\u7528 defineProperty \u53ea\u80fd\u91cd\u5b9a\u4e49\u5c5e\u6027\u7684\u8bfb\u53d6\uff08get\uff09\u548c\u8bbe\u7f6e\uff08set\uff09\u884c\u4e3a\uff0c\u5230\u4e86 ES6\uff0c\u63d0\u4f9b\u4e86 Proxy\uff0c\u53ef\u4ee5\u91cd\u5b9a\u4e49\u66f4\u591a\u7684\u884c\u4e3a\uff0c\u6bd4\u5982 in\u3001delete\u3001\u51fd\u6570\u8c03\u7528\u7b49\u66f4\u591a\u884c\u4e3a\u3002<\/p>\n
Proxy \u8fd9\u4e2a\u8bcd\u7684\u539f\u610f\u662f\u4ee3\u7406\uff0c\u7528\u5728\u8fd9\u91cc\u8868\u793a\u7531\u5b83\u6765\u201c\u4ee3\u7406\u201d\u67d0\u4e9b\u64cd\u4f5c\uff0cES6 \u539f\u751f\u63d0\u4f9b Proxy \u6784\u9020\u51fd\u6570\uff0c\u7528\u6765\u751f\u6210 Proxy \u5b9e\u4f8b\u3002\u6211\u4eec\u6765\u770b\u770b\u5b83\u7684\u8bed\u6cd5\uff1a<\/p>\n
\n
var<\/span> proxy<\/span> =<\/span> new<\/span> Proxy<\/span>(<\/span>target<\/span>,<\/span> handler<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
proxy \u5bf9\u8c61\u7684\u6240\u6709\u7528\u6cd5\uff0c\u90fd\u662f\u4e0a\u9762\u8fd9\u79cd\u5f62\u5f0f\uff0c\u4e0d\u540c\u7684\u53ea\u662fhandler\u53c2\u6570\u7684\u5199\u6cd5\u3002\u5176\u4e2d\uff0cnew Proxy()\u8868\u793a\u751f\u6210\u4e00\u4e2aProxy\u5b9e\u4f8b\uff0ctarget\u53c2\u6570\u8868\u793a\u6240\u8981\u62e6\u622a\u7684\u76ee\u6807\u5bf9\u8c61\uff0chandler\u53c2\u6570\u4e5f\u662f\u4e00\u4e2a\u5bf9\u8c61\uff0c\u7528\u6765\u5b9a\u5236\u62e6\u622a\u884c\u4e3a\u3002<\/p>\n
<\/p>\n
var<\/span> proxy<\/span> =<\/span> new<\/span> Proxy<\/span>(<\/span>{<\/span>}<\/span>,<\/span> {<\/span>\n    get<\/span>: function<\/span>(<\/span>obj<\/span>,<\/span> prop<\/span>)<\/span> {<\/span>\n        console<\/span>.<\/span>log<\/span>(<\/span>'\u8bbe\u7f6e get \u64cd\u4f5c'<\/span>)<\/span>\n        return<\/span> obj<\/span>[<\/span>prop<\/span>]<\/span>;<\/span>\n    }<\/span>,<\/span>\n    set<\/span>: function<\/span>(<\/span>obj<\/span>,<\/span> prop<\/span>,<\/span> value<\/span>)<\/span> {<\/span>\n        console<\/span>.<\/span>log<\/span>(<\/span>'\u8bbe\u7f6e set \u64cd\u4f5c'<\/span>)<\/span>\n        obj<\/span>[<\/span>prop<\/span>]<\/span> =<\/span> value<\/span>;<\/span>\n    }<\/span>\n}<\/span>)<\/span>;<\/span>\n\nproxy<\/span>.<\/span>time<\/span> =<\/span> 35<\/span>;<\/span> \/\/ \u8bbe\u7f6e set \u64cd\u4f5c<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>proxy<\/span>.<\/span>time<\/span>)<\/span>;<\/span> \/\/ \u8bbe\u7f6e get \u64cd\u4f5c \/\/ 35<\/span><\/pre>\n<\/div>\n
\u9664\u4e86 get \u548c set \u4e4b\u5916\uff0cproxy \u53ef\u4ee5\u62e6\u622a\u591a\u8fbe 13 \u79cd\u64cd\u4f5c\uff0c\u6bd4\u5982 has(target, propKey)\uff0c\u53ef\u4ee5\u62e6\u622a propKey in proxy \u7684\u64cd\u4f5c\uff0c\u8fd4\u56de\u4e00\u4e2a\u5e03\u5c14\u503c\u3002<\/p>\n
<\/p>\n
\/\/ \u4f7f\u7528 has \u65b9\u6cd5\u9690\u85cf\u67d0\u4e9b\u5c5e\u6027\uff0c\u4e0d\u88ab in \u8fd0\u7b97\u7b26\u53d1\u73b0<\/span>\nvar<\/span> handler<\/span> =<\/span> {<\/span>\n  has<\/span> (<\/span>target<\/span>,<\/span> key<\/span>)<\/span> {<\/span>\n    if<\/span> (<\/span>key<\/span>[<\/span>0<\/span>]<\/span> ===<\/span> '_'<\/span>)<\/span> {<\/span>\n      return<\/span> false<\/span>;<\/span>\n    }<\/span>\n    return<\/span> key<\/span> in<\/span> target<\/span>;<\/span>\n  }<\/span>\n}<\/span>;<\/span>\nvar<\/span> target<\/span> =<\/span> {<\/span> _prop<\/span>: 'foo'<\/span>,<\/span> prop<\/span>: 'foo'<\/span> }<\/span>;<\/span>\nvar<\/span> proxy<\/span> =<\/span> new<\/span> Proxy<\/span>(<\/span>target<\/span>,<\/span> handler<\/span>)<\/span>;<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>'_prop'<\/span> in<\/span> proxy<\/span>)<\/span>;<\/span> \/\/ false<\/span><\/pre>\n<\/div>\n
\u53c8\u6bd4\u5982\u8bf4 apply \u65b9\u6cd5\u62e6\u622a\u51fd\u6570\u7684\u8c03\u7528\u3001call \u548c apply \u64cd\u4f5c\u3002<\/p>\n
apply \u65b9\u6cd5\u53ef\u4ee5\u63a5\u53d7\u4e09\u4e2a\u53c2\u6570\uff0c\u5206\u522b\u662f\u76ee\u6807\u5bf9\u8c61\u3001\u76ee\u6807\u5bf9\u8c61\u7684\u4e0a\u4e0b\u6587\u5bf9\u8c61\uff08this\uff09\u548c\u76ee\u6807\u5bf9\u8c61\u7684\u53c2\u6570\u6570\u7ec4\uff0c\u4e0d\u8fc7\u8fd9\u91cc\u6211\u4eec\u7b80\u5355\u6f14\u793a\u4e00\u4e0b\uff1a<\/p>\n
<\/p>\n
var<\/span> target<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span> return<\/span> 'I am the target'<\/span>;<\/span> }<\/span>;<\/span>\nvar<\/span> handler<\/span> =<\/span> {<\/span>\n  apply<\/span>: function<\/span> (<\/span>)<\/span> {<\/span>\n    return<\/span> 'I am the proxy'<\/span>;<\/span>\n  }<\/span>\n}<\/span>;<\/span>\n\nvar<\/span> p<\/span> =<\/span> new<\/span> Proxy<\/span>(<\/span>target<\/span>,<\/span> handler<\/span>)<\/span>;<\/span>\n\np<\/span>(<\/span>)<\/span>;<\/span>\n\/\/ \"I am the proxy\"<\/span><\/pre>\n<\/div>\n
\u53c8\u6bd4\u5982\u8bf4 ownKeys \u65b9\u6cd5\u53ef\u4ee5\u62e6\u622a\u5bf9\u8c61\u81ea\u8eab\u5c5e\u6027\u7684\u8bfb\u53d6\u64cd\u4f5c\u3002\u5177\u4f53\u6765\u8bf4\uff0c\u62e6\u622a\u4ee5\u4e0b\u64cd\u4f5c\uff1a<\/p>\n