{"id":1382,"date":"2024-06-02T22:32:38","date_gmt":"2024-06-02T22:32:38","guid":{"rendered":""},"modified":"2024-06-05T03:10:11","modified_gmt":"2024-06-04T19:10:11","slug":"javascript%e6%b7%b1%e5%85%a5%e4%b9%8bbind%e7%9a%84%e6%a8%a1%e6%8b%9f%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/www.lccc.top\/?p=1382","title":{"rendered":"JavaScript\u6df1\u5165\u4e4bbind\u7684\u6a21\u62df\u5b9e\u73b0"},"content":{"rendered":"\n

bind<\/h2>\n

\u4e00\u53e5\u8bdd\u4ecb\u7ecd bind:<\/p>\n

\n

bind() \u65b9\u6cd5\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u51fd\u6570\u3002\u5f53\u8fd9\u4e2a\u65b0\u51fd\u6570\u88ab\u8c03\u7528\u65f6\uff0cbind() \u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u5c06\u4f5c\u4e3a\u5b83\u8fd0\u884c\u65f6\u7684 this\uff0c\u4e4b\u540e\u7684\u4e00\u5e8f\u5217\u53c2\u6570\u5c06\u4f1a\u5728\u4f20\u9012\u7684\u5b9e\u53c2\u524d\u4f20\u5165\u4f5c\u4e3a\u5b83\u7684\u53c2\u6570\u3002(\u6765\u81ea\u4e8e MDN )<\/p>\n<\/blockquote>\n

\u7531\u6b64\u6211\u4eec\u53ef\u4ee5\u9996\u5148\u5f97\u51fa bind \u51fd\u6570\u7684\u4e24\u4e2a\u7279\u70b9\uff1a<\/p>\n

    \n
  1. \u8fd4\u56de\u4e00\u4e2a\u51fd\u6570<\/li>\n
  2. \u53ef\u4ee5\u4f20\u5165\u53c2\u6570<\/li>\n<\/ol>\n

    \u8fd4\u56de\u51fd\u6570\u7684\u6a21\u62df\u5b9e\u73b0<\/h2>\n

    \u4ece\u7b2c\u4e00\u4e2a\u7279\u70b9\u5f00\u59cb\uff0c\u6211\u4eec\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n

    <\/p>\n
    var<\/span> foo<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>\n}<\/span>;<\/span>\n\nfunction<\/span> bar<\/span>(<\/span>)<\/span> {<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>this<\/span>.<\/span>value<\/span>)<\/span>;<\/span>\n}<\/span>\n\n\/\/ \u8fd4\u56de\u4e86\u4e00\u4e2a\u51fd\u6570<\/span>\nvar<\/span> bindFoo<\/span> =<\/span> bar<\/span>.<\/span>bind<\/span>(<\/span>foo<\/span>)<\/span>;<\/span> \n\nbindFoo<\/span>(<\/span>)<\/span>;<\/span> \/\/ 1<\/span><\/pre>\n<\/div>\n
    \u5173\u4e8e\u6307\u5b9a this \u7684\u6307\u5411\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528 call \u6216\u8005 apply \u5b9e\u73b0\uff0c\u5173\u4e8e call \u548c apply \u7684\u6a21\u62df\u5b9e\u73b0\uff0c\u53ef\u4ee5\u67e5\u770b\u300aJavaScript\u6df1\u5165\u4e4bcall\u548capply\u7684\u6a21\u62df\u5b9e\u73b0\u300b<\/a>\u3002\u6211\u4eec\u6765\u5199\u7b2c\u4e00\u7248\u7684\u4ee3\u7801\uff1a<\/p>\n
    <\/p>\n
    \/\/ \u7b2c\u4e00\u7248<\/span>\nFunction<\/span>.<\/span>prototype<\/span>.<\/span>bind2<\/span> =<\/span> function<\/span> (<\/span>context<\/span>)<\/span> {<\/span>\n    var<\/span> self<\/span> =<\/span> this<\/span>;<\/span>\n    return<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n        return<\/span> self<\/span>.<\/span>apply<\/span>(<\/span>context<\/span>)<\/span>;<\/span>\n    }<\/span>\n\n}<\/span><\/pre>\n<\/div>\n
    \u6b64\u5916\uff0c\u4e4b\u6240\u4ee5 return self.apply(context)<\/code>\uff0c\u662f\u8003\u8651\u5230\u7ed1\u5b9a\u51fd\u6570\u53ef\u80fd\u662f\u6709\u8fd4\u56de\u503c\u7684\uff0c\u4f9d\u7136\u662f\u8fd9\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
    <\/p>\n
    var<\/span> foo<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>\n}<\/span>;<\/span>\n\nfunction<\/span> bar<\/span>(<\/span>)<\/span> {<\/span>\n\treturn<\/span> this<\/span>.<\/span>value<\/span>;<\/span>\n}<\/span>\n\nvar<\/span> bindFoo<\/span> =<\/span> bar<\/span>.<\/span>bind<\/span>(<\/span>foo<\/span>)<\/span>;<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>bindFoo<\/span>(<\/span>)<\/span>)<\/span>;<\/span> \/\/ 1<\/span><\/pre>\n<\/div>\n
    \u4f20\u53c2\u7684\u6a21\u62df\u5b9e\u73b0<\/h2>\n
    \u63a5\u4e0b\u6765\u770b\u7b2c\u4e8c\u70b9\uff0c\u53ef\u4ee5\u4f20\u5165\u53c2\u6570\u3002\u8fd9\u4e2a\u5c31\u6709\u70b9\u8ba9\u4eba\u8d39\u89e3\u4e86\uff0c\u6211\u5728 bind \u7684\u65f6\u5019\uff0c\u662f\u5426\u53ef\u4ee5\u4f20\u53c2\u5462\uff1f\u6211\u5728\u6267\u884c bind \u8fd4\u56de\u7684\u51fd\u6570\u7684\u65f6\u5019\uff0c\u53ef\u4e0d\u53ef\u4ee5\u4f20\u53c2\u5462\uff1f\u8ba9\u6211\u4eec\u770b\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
    <\/p>\n
    var<\/span> foo<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>\n}<\/span>;<\/span>\n\nfunction<\/span> bar<\/span>(<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>this<\/span>.<\/span>value<\/span>)<\/span>;<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>name<\/span>)<\/span>;<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>age<\/span>)<\/span>;<\/span>\n\n}<\/span>\n\nvar<\/span> bindFoo<\/span> =<\/span> bar<\/span>.<\/span>bind<\/span>(<\/span>foo<\/span>,<\/span> 'daisy'<\/span>)<\/span>;<\/span>\nbindFoo<\/span>(<\/span>'18'<\/span>)<\/span>;<\/span>\n\/\/ 1<\/span>\n\/\/ daisy<\/span>\n\/\/ 18<\/span><\/pre>\n<\/div>\n
    \u51fd\u6570\u9700\u8981\u4f20 name \u548c age \u4e24\u4e2a\u53c2\u6570\uff0c\u7adf\u7136\u8fd8\u53ef\u4ee5\u5728 bind \u7684\u65f6\u5019\uff0c\u53ea\u4f20\u4e00\u4e2a name\uff0c\u5728\u6267\u884c\u8fd4\u56de\u7684\u51fd\u6570\u7684\u65f6\u5019\uff0c\u518d\u4f20\u53e6\u4e00\u4e2a\u53c2\u6570 age!<\/p>\n
    \u8fd9\u53ef\u548b\u529e\uff1f\u4e0d\u6025\uff0c\u6211\u4eec\u7528 arguments \u8fdb\u884c\u5904\u7406\uff1a<\/p>\n
    <\/p>\n
    \/\/ \u7b2c\u4e8c\u7248<\/span>\nFunction<\/span>.<\/span>prototype<\/span>.<\/span>bind2<\/span> =<\/span> function<\/span> (<\/span>context<\/span>)<\/span> {<\/span>\n\n    var<\/span> self<\/span> =<\/span> this<\/span>;<\/span>\n    \/\/ \u83b7\u53d6bind2\u51fd\u6570\u4ece\u7b2c\u4e8c\u4e2a\u53c2\u6570\u5230\u6700\u540e\u4e00\u4e2a\u53c2\u6570<\/span>\n    var<\/span> args<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>,<\/span> 1<\/span>)<\/span>;<\/span>\n\n    return<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n        \/\/ \u8fd9\u4e2a\u65f6\u5019\u7684arguments\u662f\u6307bind\u8fd4\u56de\u7684\u51fd\u6570\u4f20\u5165\u7684\u53c2\u6570<\/span>\n        var<\/span> bindArgs<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>)<\/span>;<\/span>\n        return<\/span> self<\/span>.<\/span>apply<\/span>(<\/span>context<\/span>,<\/span> args<\/span>.<\/span>concat<\/span>(<\/span>bindArgs<\/span>)<\/span>)<\/span>;<\/span>\n    }<\/span>\n\n}<\/span><\/pre>\n<\/div>\n
    \u6784\u9020\u51fd\u6570\u6548\u679c\u7684\u6a21\u62df\u5b9e\u73b0<\/h2>\n
    \u5b8c\u6210\u4e86\u8fd9\u4e24\u70b9\uff0c\u6700\u96be\u7684\u90e8\u5206\u5230\u5566\uff01\u56e0\u4e3a bind \u8fd8\u6709\u4e00\u4e2a\u7279\u70b9\uff0c\u5c31\u662f<\/p>\n
    \n
    \u4e00\u4e2a\u7ed1\u5b9a\u51fd\u6570\u4e5f\u80fd\u4f7f\u7528new\u64cd\u4f5c\u7b26\u521b\u5efa\u5bf9\u8c61\uff1a\u8fd9\u79cd\u884c\u4e3a\u5c31\u50cf\u628a\u539f\u51fd\u6570\u5f53\u6210\u6784\u9020\u5668\u3002\u63d0\u4f9b\u7684 this \u503c\u88ab\u5ffd\u7565\uff0c\u540c\u65f6\u8c03\u7528\u65f6\u7684\u53c2\u6570\u88ab\u63d0\u4f9b\u7ed9\u6a21\u62df\u51fd\u6570\u3002<\/p>\n<\/blockquote>\n
    \u4e5f\u5c31\u662f\u8bf4\u5f53 bind \u8fd4\u56de\u7684\u51fd\u6570\u4f5c\u4e3a\u6784\u9020\u51fd\u6570\u7684\u65f6\u5019\uff0cbind \u65f6\u6307\u5b9a\u7684 this \u503c\u4f1a\u5931\u6548\uff0c\u4f46\u4f20\u5165\u7684\u53c2\u6570\u4f9d\u7136\u751f\u6548\u3002\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
    <\/p>\n
    var<\/span> value<\/span> =<\/span> 2<\/span>;<\/span>\n\nvar<\/span> foo<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>\n}<\/span>;<\/span>\n\nfunction<\/span> bar<\/span>(<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n    this<\/span>.<\/span>habit<\/span> =<\/span> 'shopping'<\/span>;<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>this<\/span>.<\/span>value<\/span>)<\/span>;<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>name<\/span>)<\/span>;<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>age<\/span>)<\/span>;<\/span>\n}<\/span>\n\nbar<\/span>.<\/span>prototype<\/span>.<\/span>friend<\/span> =<\/span> 'kevin'<\/span>;<\/span>\n\nvar<\/span> bindFoo<\/span> =<\/span> bar<\/span>.<\/span>bind<\/span>(<\/span>foo<\/span>,<\/span> 'daisy'<\/span>)<\/span>;<\/span>\n\nvar<\/span> obj<\/span> =<\/span> new<\/span> bindFoo<\/span>(<\/span>'18'<\/span>)<\/span>;<\/span>\n\/\/ undefined<\/span>\n\/\/ daisy<\/span>\n\/\/ 18<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>obj<\/span>.<\/span>habit<\/span>)<\/span>;<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>obj<\/span>.<\/span>friend<\/span>)<\/span>;<\/span>\n\/\/ shopping<\/span>\n\/\/ kevin<\/span><\/pre>\n<\/div>\n
    \u6ce8\u610f\uff1a\u5c3d\u7ba1\u5728\u5168\u5c40\u548c foo \u4e2d\u90fd\u58f0\u660e\u4e86 value \u503c\uff0c\u6700\u540e\u4f9d\u7136\u8fd4\u56de\u4e86 undefind\uff0c\u8bf4\u660e\u7ed1\u5b9a\u7684 this \u5931\u6548\u4e86\uff0c\u5982\u679c\u5927\u5bb6\u4e86\u89e3 new \u7684\u6a21\u62df\u5b9e\u73b0\uff0c\u5c31\u4f1a\u77e5\u9053\u8fd9\u4e2a\u65f6\u5019\u7684 this \u5df2\u7ecf\u6307\u5411\u4e86 obj\u3002<\/p>\n
    (\u54c8\u54c8\uff0c\u6211\u8fd9\u662f\u4e3a\u6211\u7684\u4e0b\u4e00\u7bc7\u6587\u7ae0\u300aJavaScript\u6df1\u5165\u7cfb\u5217\u4e4bnew\u7684\u6a21\u62df\u5b9e\u73b0\u300b<\/a>\u6253\u5e7f\u544a)\u3002<\/p>\n
    \u6240\u4ee5\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4fee\u6539\u8fd4\u56de\u7684\u51fd\u6570\u7684\u539f\u578b\u6765\u5b9e\u73b0\uff0c\u8ba9\u6211\u4eec\u5199\u4e00\u4e0b\uff1a<\/p>\n
    <\/p>\n
    \/\/ \u7b2c\u4e09\u7248<\/span>\nFunction<\/span>.<\/span>prototype<\/span>.<\/span>bind2<\/span> =<\/span> function<\/span> (<\/span>context<\/span>)<\/span> {<\/span>\n    var<\/span> self<\/span> =<\/span> this<\/span>;<\/span>\n    var<\/span> args<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>,<\/span> 1<\/span>)<\/span>;<\/span>\n\n    var<\/span> fBound<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n        var<\/span> bindArgs<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>)<\/span>;<\/span>\n        \/\/ \u5f53\u4f5c\u4e3a\u6784\u9020\u51fd\u6570\u65f6\uff0cthis \u6307\u5411\u5b9e\u4f8b\uff0c\u6b64\u65f6\u7ed3\u679c\u4e3a true\uff0c\u5c06\u7ed1\u5b9a\u51fd\u6570\u7684 this \u6307\u5411\u8be5\u5b9e\u4f8b\uff0c\u53ef\u4ee5\u8ba9\u5b9e\u4f8b\u83b7\u5f97\u6765\u81ea\u7ed1\u5b9a\u51fd\u6570\u7684\u503c<\/span>\n        \/\/ \u4ee5\u4e0a\u9762\u7684\u662f demo \u4e3a\u4f8b\uff0c\u5982\u679c\u6539\u6210 `this instanceof fBound ? null : context`\uff0c\u5b9e\u4f8b\u53ea\u662f\u4e00\u4e2a\u7a7a\u5bf9\u8c61\uff0c\u5c06 null \u6539\u6210 this \uff0c\u5b9e\u4f8b\u4f1a\u5177\u6709 habit \u5c5e\u6027<\/span>\n        \/\/ \u5f53\u4f5c\u4e3a\u666e\u901a\u51fd\u6570\u65f6\uff0cthis \u6307\u5411 window\uff0c\u6b64\u65f6\u7ed3\u679c\u4e3a false\uff0c\u5c06\u7ed1\u5b9a\u51fd\u6570\u7684 this \u6307\u5411 context<\/span>\n        return<\/span> self<\/span>.<\/span>apply<\/span>(<\/span>this<\/span> instanceof<\/span> fBound<\/span> ? this<\/span> : context<\/span>,<\/span> args<\/span>.<\/span>concat<\/span>(<\/span>bindArgs<\/span>)<\/span>)<\/span>;<\/span>\n    }<\/span>\n    \/\/ \u4fee\u6539\u8fd4\u56de\u51fd\u6570\u7684 prototype \u4e3a\u7ed1\u5b9a\u51fd\u6570\u7684 prototype\uff0c\u5b9e\u4f8b\u5c31\u53ef\u4ee5\u7ee7\u627f\u7ed1\u5b9a\u51fd\u6570\u7684\u539f\u578b\u4e2d\u7684\u503c<\/span>\n    fBound<\/span>.<\/span>prototype<\/span> =<\/span> this<\/span>.<\/span>prototype<\/span>;<\/span>\n    return<\/span> fBound<\/span>;<\/span>\n}<\/span><\/pre>\n<\/div>\n
    \u5982\u679c\u5bf9\u539f\u578b\u94fe\u7a0d\u6709\u56f0\u60d1\uff0c\u53ef\u4ee5\u67e5\u770b\u300aJavaScript\u6df1\u5165\u4e4b\u4ece\u539f\u578b\u5230\u539f\u578b\u94fe\u300b<\/a>\u3002<\/p>\n
    \u6784\u9020\u51fd\u6570\u6548\u679c\u7684\u4f18\u5316\u5b9e\u73b0<\/h2>\n
    \u4f46\u662f\u5728\u8fd9\u4e2a\u5199\u6cd5\u4e2d\uff0c\u6211\u4eec\u76f4\u63a5\u5c06 fBound.prototype = this.prototype\uff0c\u6211\u4eec\u76f4\u63a5\u4fee\u6539 fBound.prototype \u7684\u65f6\u5019\uff0c\u4e5f\u4f1a\u76f4\u63a5\u4fee\u6539\u7ed1\u5b9a\u51fd\u6570\u7684 prototype\u3002\u8fd9\u4e2a\u65f6\u5019\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u4e00\u4e2a\u7a7a\u51fd\u6570\u6765\u8fdb\u884c\u4e2d\u8f6c\uff1a<\/p>\n
    <\/p>\n
    \/\/ \u7b2c\u56db\u7248<\/span>\nFunction<\/span>.<\/span>prototype<\/span>.<\/span>bind2<\/span> =<\/span> function<\/span> (<\/span>context<\/span>)<\/span> {<\/span>\n\n    var<\/span> self<\/span> =<\/span> this<\/span>;<\/span>\n    var<\/span> args<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>,<\/span> 1<\/span>)<\/span>;<\/span>\n\n    var<\/span> fNOP<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span>}<\/span>;<\/span>\n\n    var<\/span> fBound<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n        var<\/span> bindArgs<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>)<\/span>;<\/span>\n        return<\/span> self<\/span>.<\/span>apply<\/span>(<\/span>this<\/span> instanceof<\/span> fNOP<\/span> ? this<\/span> : context<\/span>,<\/span> args<\/span>.<\/span>concat<\/span>(<\/span>bindArgs<\/span>)<\/span>)<\/span>;<\/span>\n    }<\/span>\n\n    fNOP<\/span>.<\/span>prototype<\/span> =<\/span> this<\/span>.<\/span>prototype<\/span>;<\/span>\n    fBound<\/span>.<\/span>prototype<\/span> =<\/span> new<\/span> fNOP<\/span>(<\/span>)<\/span>;<\/span>\n    return<\/span> fBound<\/span>;<\/span>\n}<\/span><\/pre>\n<\/div>\n
    \u5230\u6b64\u4e3a\u6b62\uff0c\u5927\u7684\u95ee\u9898\u90fd\u5df2\u7ecf\u89e3\u51b3\uff0c\u7ed9\u81ea\u5df1\u4e00\u4e2a\u8d5e\uff01o(\uffe3\u25bd\uffe3)\uff44<\/p>\n
    \u4e09\u4e2a\u5c0f\u95ee\u9898<\/h2>\n
    \u63a5\u4e0b\u6765\u5904\u7406\u4e9b\u5c0f\u95ee\u9898:<\/p>\n
    1.apply \u8fd9\u6bb5\u4ee3\u7801\u8ddf MDN \u4e0a\u7684\u7a0d\u6709\u4e0d\u540c<\/strong><\/p>\n
    \u5728 MDN \u4e2d\u6587\u7248\u8bb2 bind \u7684\u6a21\u62df\u5b9e\u73b0\u65f6\uff0capply \u8fd9\u91cc\u7684\u4ee3\u7801\u662f\uff1a<\/p>\n
    <\/p>\n
    self<\/span>.<\/span>apply<\/span>(<\/span>this<\/span> instanceof<\/span> self<\/span> ? this<\/span> : context<\/span> ||<\/span> this<\/span>,<\/span> args<\/span>.<\/span>concat<\/span>(<\/span>bindArgs<\/span>)<\/span>)<\/span><\/pre>\n<\/div>\n
    \u591a\u4e86\u4e00\u4e2a\u5173\u4e8e context \u662f\u5426\u5b58\u5728\u7684\u5224\u65ad\uff0c\u7136\u800c\u8fd9\u4e2a\u662f\u9519\u8bef\u7684\uff01<\/p>\n
    \u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
    <\/p>\n
    var<\/span> value<\/span> =<\/span> 2<\/span>;<\/span>\nvar<\/span> foo<\/span> =<\/span> {<\/span>\n    value<\/span>: 1<\/span>,<\/span>\n    bar<\/span>: bar<\/span>.<\/span>bind<\/span>(<\/span>null<\/span>)<\/span>\n}<\/span>;<\/span>\n\nfunction<\/span> bar<\/span>(<\/span>)<\/span> {<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>this<\/span>.<\/span>value<\/span>)<\/span>;<\/span>\n}<\/span>\n\nfoo<\/span>.<\/span>bar<\/span>(<\/span>)<\/span> \/\/ 2<\/span><\/pre>\n<\/div>\n
    \u4ee5\u4e0a\u4ee3\u7801\u6b63\u5e38\u60c5\u51b5\u4e0b\u4f1a\u6253\u5370 2\uff0c\u5982\u679c\u6362\u6210\u4e86 context || this\uff0c\u8fd9\u6bb5\u4ee3\u7801\u5c31\u4f1a\u6253\u5370 1\uff01<\/p>\n
    \u6240\u4ee5\u8fd9\u91cc\u4e0d\u5e94\u8be5\u8fdb\u884c context \u7684\u5224\u65ad\uff0c\u5927\u5bb6\u67e5\u770b MDN \u540c\u6837\u5185\u5bb9\u7684\u82f1\u6587\u7248\uff0c\u5c31\u4e0d\u5b58\u5728\u8fd9\u4e2a\u5224\u65ad\uff01<\/p>\n
    (2018\u5e743\u670827\u65e5\u66f4\u65b0\uff0c\u4e2d\u6587\u7248\u5df2\u7ecf\u6539\u4e86?)<\/p>\n
    2.\u8c03\u7528 bind \u7684\u4e0d\u662f\u51fd\u6570\u548b\u529e\uff1f<\/strong><\/p>\n
    \u4e0d\u884c\uff0c\u6211\u4eec\u8981\u62a5\u9519\uff01<\/p>\n
    <\/p>\n
    if<\/span> (<\/span>typeof<\/span> this<\/span> !==<\/span> \"function\"<\/span>)<\/span> {<\/span>\n  throw<\/span> new<\/span> Error<\/span>(<\/span>\"Function.prototype.bind - what is trying to be bound is not callable\"<\/span>)<\/span>;<\/span>\n}<\/span><\/pre>\n<\/div>\n
    3.\u6211\u8981\u5728\u7ebf\u4e0a\u7528<\/strong><\/p>\n
    \u90a3\u522b\u5fd8\u4e86\u505a\u4e2a\u517c\u5bb9\uff1a<\/p>\n
    <\/p>\n
    Function<\/span>.<\/span>prototype<\/span>.<\/span>bind<\/span> =<\/span> Function<\/span>.<\/span>prototype<\/span>.<\/span>bind<\/span> ||<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n    \u2026\u2026<\/span>\n}<\/span>;<\/span><\/pre>\n<\/div>\n
    \u5f53\u7136\u6700\u597d\u662f\u7528 es5-shim<\/a> \u5566\u3002<\/p>\n
    \u6700\u7ec8\u4ee3\u7801<\/h2>\n
    \u6240\u4ee5\u6700\u6700\u540e\u7684\u4ee3\u7801\u5c31\u662f\uff1a<\/p>\n
    <\/p>\n
    Function<\/span>.<\/span>prototype<\/span>.<\/span>bind2<\/span> =<\/span> function<\/span> (<\/span>context<\/span>)<\/span> {<\/span>\n\n    if<\/span> (<\/span>typeof<\/span> this<\/span> !==<\/span> \"function\"<\/span>)<\/span> {<\/span>\n      throw<\/span> new<\/span> Error<\/span>(<\/span>\"Function.prototype.bind - what is trying to be bound is not callable\"<\/span>)<\/span>;<\/span>\n    }<\/span>\n\n    var<\/span> self<\/span> =<\/span> this<\/span>;<\/span>\n    var<\/span> args<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>,<\/span> 1<\/span>)<\/span>;<\/span>\n\n    var<\/span> fNOP<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span>}<\/span>;<\/span>\n\n    var<\/span> fBound<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n        var<\/span> bindArgs<\/span> =<\/span> Array<\/span>.<\/span>prototype<\/span>.<\/span>slice<\/span>.<\/span>call<\/span>(<\/span>arguments<\/span>)<\/span>;<\/span>\n        return<\/span> self<\/span>.<\/span>apply<\/span>(<\/span>this<\/span> instanceof<\/span> fNOP<\/span> ? this<\/span> : context<\/span>,<\/span> args<\/span>.<\/span>concat<\/span>(<\/span>bindArgs<\/span>)<\/span>)<\/span>;<\/span>\n    }<\/span>\n\n    fNOP<\/span>.<\/span>prototype<\/span> =<\/span> this<\/span>.<\/span>prototype<\/span>;<\/span>\n    fBound<\/span>.<\/span>prototype<\/span> =<\/span> new<\/span> fNOP<\/span>(<\/span>)<\/span>;<\/span>\n    return<\/span> fBound<\/span>;<\/span>\n}<\/span><\/pre>\n<\/div>\n
    \u4e0b\u4e00\u7bc7\u6587\u7ae0<\/h2>\n
    \u300aJavaScript\u6df1\u5165\u7cfb\u5217\u4e4bnew\u7684\u6a21\u62df\u5b9e\u73b0\u300b<\/a><\/p>\n
    \u76f8\u5173\u94fe\u63a5<\/h2>\n
    \u300aJavaScript\u6df1\u5165\u4e4b\u4ece\u539f\u578b\u5230\u539f\u578b\u94fe\u300b<\/a><\/p>\n
    \u300aJavaScript\u6df1\u5165\u4e4bcall\u548capply\u7684\u6a21\u62df\u5b9e\u73b0\u300b<\/a><\/p>\n
    \u300aJavaScript\u6df1\u5165\u7cfb\u5217\u4e4bnew\u7684\u6a21\u62df\u5b9e\u73b0\u300b<\/a><\/p>\n
    \u6df1\u5165\u7cfb\u5217<\/h2>\n
    JavaScript\u6df1\u5165\u7cfb\u5217\u76ee\u5f55\u5730\u5740\uff1ahttps:\/\/github.com\/mqyqingfeng\/Blog<\/a>\u3002<\/p>\n
    JavaScript\u6df1\u5165\u7cfb\u5217\u9884\u8ba1\u5199\u5341\u4e94\u7bc7\u5de6\u53f3\uff0c\u65e8\u5728\u5e2e\u5927\u5bb6\u634b\u987aJavaScript\u5e95\u5c42\u77e5\u8bc6\uff0c\u91cd\u70b9\u8bb2\u89e3\u5982\u539f\u578b\u3001\u4f5c\u7528\u57df\u3001\u6267\u884c\u4e0a\u4e0b\u6587\u3001\u53d8\u91cf\u5bf9\u8c61\u3001this\u3001\u95ed\u5305\u3001\u6309\u503c\u4f20\u9012\u3001call\u3001apply\u3001bind\u3001new\u3001\u7ee7\u627f\u7b49\u96be\u70b9\u6982\u5ff5\u3002<\/p>\n
    \u5982\u679c\u6709\u9519\u8bef\u6216\u8005\u4e0d\u4e25\u8c28\u7684\u5730\u65b9\uff0c\u8bf7\u52a1\u5fc5\u7ed9\u4e88\u6307\u6b63\uff0c\u5341\u5206\u611f\u8c22\u3002\u5982\u679c\u559c\u6b22\u6216\u8005\u6709\u6240\u542f\u53d1\uff0c\u6b22\u8fcestar\uff0c\u5bf9\u4f5c\u8005\u4e5f\u662f\u4e00\u79cd\u9f13\u52b1\u3002<\/p>\n<\/td>\n
    \u6587\u7ae0\u8f6c\u8f7d\u81eahttps:\/\/github.com\/mqyqingfeng\/Blog\/issues\/12<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
    bind \u4e00\u53e5\u8bdd\u4ecb\u7ecd bind: bind() \u65b9\u6cd5\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u51fd\u6570\u3002\u5f53\u8fd9\u4e2a\u65b0\u51fd\u6570\u88ab\u8c03\u7528\u65f6\uff0cbind() \u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u5c06\u4f5c\u4e3a\u5b83\u8fd0\u884c\u65f6\u7684 this\uff0c\u4e4b\u540e\u7684\u4e00\u5e8f\u5217\u53c2…<\/p>\n
     Read More  Read More<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1382","post","type-post","status-publish","format-standard","hentry","category-learn"],"_links":{"self":[{"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts\/1382"}],"collection":[{"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1382"}],"version-history":[{"count":1,"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts\/1382\/revisions"}],"predecessor-version":[{"id":1499,"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts\/1382\/revisions\/1499"}],"wp:attachment":[{"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1382"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}