{"id":1358,"date":"2024-06-02T22:21:57","date_gmt":"2024-06-02T22:21:57","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-babel-%e6%98%af%e5%a6%82%e4%bd%95%e7%bc%96%e8%af%91-class-%e7%9a%84%e4%b8%8b","status":"publish","type":"post","link":"https:\/\/www.lccc.top\/?p=1358","title":{"rendered":"ES6 \u7cfb\u5217\u4e4b Babel \u662f\u5982\u4f55\u7f16\u8bd1 Class \u7684(\u4e0b)"},"content":{"rendered":"\n

\u524d\u8a00<\/h2>\n

\u5728\u4e0a\u4e00\u7bc7 \u300a ES6 \u7cfb\u5217 Babel \u662f\u5982\u4f55\u7f16\u8bd1 Class \u7684(\u4e0a)\u300b<\/a>\uff0c\u6211\u4eec\u77e5\u9053\u4e86 Babel \u662f\u5982\u4f55\u7f16\u8bd1 Class \u7684\uff0c\u8fd9\u7bc7\u6211\u4eec\u5b66\u4e60 Babel \u662f\u5982\u4f55\u7528 ES5 \u5b9e\u73b0 Class \u7684\u7ee7\u627f\u3002<\/p>\n

ES5 \u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f<\/h2>\n
<\/p>\n
function<\/span> Parent<\/span> (<\/span>name<\/span>)<\/span> {<\/span>\n    this<\/span>.<\/span>name<\/span> =<\/span> name<\/span>;<\/span>\n}<\/span>\n\nParent<\/span>.<\/span>prototype<\/span>.<\/span>getName<\/span> =<\/span> function<\/span> (<\/span>)<\/span> {<\/span>\n    console<\/span>.<\/span>log<\/span>(<\/span>this<\/span>.<\/span>name<\/span>)<\/span>\n}<\/span>\n\nfunction<\/span> Child<\/span> (<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n    Parent<\/span>.<\/span>call<\/span>(<\/span>this<\/span>,<\/span> name<\/span>)<\/span>;<\/span>\n    this<\/span>.<\/span>age<\/span> =<\/span> age<\/span>;<\/span>\n}<\/span>\n\nChild<\/span>.<\/span>prototype<\/span> =<\/span> Object<\/span>.<\/span>create<\/span>(<\/span>Parent<\/span>.<\/span>prototype<\/span>)<\/span>;<\/span>\n\nvar<\/span> child1<\/span> =<\/span> new<\/span> Child<\/span>(<\/span>'kevin'<\/span>,<\/span> '18'<\/span>)<\/span>;<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>child1<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u539f\u578b\u94fe\u793a\u610f\u56fe\u4e3a\uff1a<\/p>\n
\"\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\u539f\u578b\u94fe\u793a\u610f\u56fe\"<\/a><\/p>\n
\u5173\u4e8e\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\u6211\u4eec\u5728 \u300aJavaScript\u6df1\u5165\u4e4b\u7ee7\u627f\u7684\u591a\u79cd\u65b9\u5f0f\u548c\u4f18\u7f3a\u70b9\u300b<\/a> \u4e2d\u4ecb\u7ecd\u8fc7\u3002<\/p>\n
\u5f15\u7528\u300aJavaScript\u9ad8\u7ea7\u7a0b\u5e8f\u8bbe\u8ba1\u300b\u4e2d\u5bf9\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\u7684\u5938\u8d5e\u5c31\u662f\uff1a<\/p>\n
\n
\u8fd9\u79cd\u65b9\u5f0f\u7684\u9ad8\u6548\u7387\u4f53\u73b0\u5b83\u53ea\u8c03\u7528\u4e86\u4e00\u6b21 Parent \u6784\u9020\u51fd\u6570\uff0c\u5e76\u4e14\u56e0\u6b64\u907f\u514d\u4e86\u5728 Parent.prototype \u4e0a\u9762\u521b\u5efa\u4e0d\u5fc5\u8981\u7684\u3001\u591a\u4f59\u7684\u5c5e\u6027\u3002\u4e0e\u6b64\u540c\u65f6\uff0c\u539f\u578b\u94fe\u8fd8\u80fd\u4fdd\u6301\u4e0d\u53d8\uff1b\u56e0\u6b64\uff0c\u8fd8\u80fd\u591f\u6b63\u5e38\u4f7f\u7528 instanceof \u548c isPrototypeOf\u3002\u5f00\u53d1\u4eba\u5458\u666e\u904d\u8ba4\u4e3a\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\u662f\u5f15\u7528\u7c7b\u578b\u6700\u7406\u60f3\u7684\u7ee7\u627f\u8303\u5f0f\u3002<\/p>\n<\/blockquote>\n
ES6 extend<\/h2>\n
Class \u901a\u8fc7 extends \u5173\u952e\u5b57\u5b9e\u73b0\u7ee7\u627f\uff0c\u8fd9\u6bd4 ES5 \u7684\u901a\u8fc7\u4fee\u6539\u539f\u578b\u94fe\u5b9e\u73b0\u7ee7\u627f\uff0c\u8981\u6e05\u6670\u548c\u65b9\u4fbf\u5f88\u591a\u3002<\/p>\n
\u4ee5\u4e0a ES5 \u7684\u4ee3\u7801\u5bf9\u5e94\u5230 ES6 \u5c31\u662f\uff1a<\/p>\n
<\/p>\n
class<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>name<\/span>)<\/span> {<\/span>\n        this<\/span>.<\/span>name<\/span> =<\/span> name<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\nclass<\/span> Child<\/span> extends<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n        super<\/span>(<\/span>name<\/span>)<\/span>;<\/span> \/\/ \u8c03\u7528\u7236\u7c7b\u7684 constructor(name)<\/span>\n        this<\/span>.<\/span>age<\/span> =<\/span> age<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\nvar<\/span> child1<\/span> =<\/span> new<\/span> Child<\/span>(<\/span>'kevin'<\/span>,<\/span> '18'<\/span>)<\/span>;<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>child1<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff1a<\/p>\n
super \u5173\u952e\u5b57\u8868\u793a\u7236\u7c7b\u7684\u6784\u9020\u51fd\u6570\uff0c\u76f8\u5f53\u4e8e ES5 \u7684 Parent.call(this)\u3002<\/p>\n
\u5b50\u7c7b\u5fc5\u987b\u5728 constructor \u65b9\u6cd5\u4e2d\u8c03\u7528 super \u65b9\u6cd5\uff0c\u5426\u5219\u65b0\u5efa\u5b9e\u4f8b\u65f6\u4f1a\u62a5\u9519\u3002\u8fd9\u662f\u56e0\u4e3a\u5b50\u7c7b\u6ca1\u6709\u81ea\u5df1\u7684 this \u5bf9\u8c61\uff0c\u800c\u662f\u7ee7\u627f\u7236\u7c7b\u7684 this \u5bf9\u8c61\uff0c\u7136\u540e\u5bf9\u5176\u8fdb\u884c\u52a0\u5de5\u3002\u5982\u679c\u4e0d\u8c03\u7528 super \u65b9\u6cd5\uff0c\u5b50\u7c7b\u5c31\u5f97\u4e0d\u5230 this \u5bf9\u8c61\u3002<\/p>\n
\u4e5f\u6b63\u662f\u56e0\u4e3a\u8fd9\u4e2a\u539f\u56e0\uff0c\u5728\u5b50\u7c7b\u7684\u6784\u9020\u51fd\u6570\u4e2d\uff0c\u53ea\u6709\u8c03\u7528 super \u4e4b\u540e\uff0c\u624d\u53ef\u4ee5\u4f7f\u7528 this \u5173\u952e\u5b57\uff0c\u5426\u5219\u4f1a\u62a5\u9519\u3002<\/p>\n
\u5b50\u7c7b\u7684 __proto__<\/h2>\n
\u5728 ES6 \u4e2d\uff0c\u7236\u7c7b\u7684\u9759\u6001\u65b9\u6cd5\uff0c\u53ef\u4ee5\u88ab\u5b50\u7c7b\u7ee7\u627f\u3002\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
<\/p>\n
class<\/span> Foo<\/span> {<\/span>\n  static<\/span> classMethod<\/span>(<\/span>)<\/span> {<\/span>\n    return<\/span> 'hello'<\/span>;<\/span>\n  }<\/span>\n}<\/span>\n\nclass<\/span> Bar<\/span> extends<\/span> Foo<\/span> {<\/span>\n}<\/span>\n\nBar<\/span>.<\/span>classMethod<\/span>(<\/span>)<\/span>;<\/span> \/\/ 'hello'<\/span><\/pre>\n<\/div>\n
\u8fd9\u662f\u56e0\u4e3a Class \u4f5c\u4e3a\u6784\u9020\u51fd\u6570\u7684\u8bed\u6cd5\u7cd6\uff0c\u540c\u65f6\u6709 prototype \u5c5e\u6027\u548c __proto__ \u5c5e\u6027\uff0c\u56e0\u6b64\u540c\u65f6\u5b58\u5728\u4e24\u6761\u7ee7\u627f\u94fe\u3002<\/p>\n
\uff081\uff09\u5b50\u7c7b\u7684 __proto__ \u5c5e\u6027\uff0c\u8868\u793a\u6784\u9020\u51fd\u6570\u7684\u7ee7\u627f\uff0c\u603b\u662f\u6307\u5411\u7236\u7c7b\u3002<\/p>\n
\uff082\uff09\u5b50\u7c7b prototype \u5c5e\u6027\u7684 __proto__ \u5c5e\u6027\uff0c\u8868\u793a\u65b9\u6cd5\u7684\u7ee7\u627f\uff0c\u603b\u662f\u6307\u5411\u7236\u7c7b\u7684 prototype \u5c5e\u6027\u3002<\/p>\n
<\/p>\n
class<\/span> Parent<\/span> {<\/span>\n}<\/span>\n\nclass<\/span> Child<\/span> extends<\/span> Parent<\/span> {<\/span>\n}<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>Child<\/span>.<\/span>__proto__<\/span> ===<\/span> Parent<\/span>)<\/span>;<\/span> \/\/ true<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>Child<\/span>.<\/span>prototype<\/span>.<\/span>__proto__<\/span> ===<\/span> Parent<\/span>.<\/span>prototype<\/span>)<\/span>;<\/span> \/\/ true<\/span><\/pre>\n<\/div>\n
ES6 \u7684\u539f\u578b\u94fe\u793a\u610f\u56fe\u4e3a\uff1a<\/p>\n
\"ES6<\/a><\/p>\n
\u6211\u4eec\u4f1a\u53d1\u73b0\uff0c\u76f8\u6bd4\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\uff0cES6 \u7684 class \u591a\u4e86\u4e00\u4e2a Object.setPrototypeOf(Child, Parent)<\/code> \u7684\u6b65\u9aa4\u3002<\/p>\n
\u7ee7\u627f\u76ee\u6807<\/h2>\n
extends \u5173\u952e\u5b57\u540e\u9762\u53ef\u4ee5\u8ddf\u591a\u79cd\u7c7b\u578b\u7684\u503c\u3002<\/p>\n
<\/p>\n
class<\/span> B<\/span> extends<\/span> A<\/span> {<\/span>\n}<\/span><\/pre>\n<\/div>\n
\u4e0a\u9762\u4ee3\u7801\u7684 A\uff0c\u53ea\u8981\u662f\u4e00\u4e2a\u6709 prototype \u5c5e\u6027\u7684\u51fd\u6570\uff0c\u5c31\u80fd\u88ab B \u7ee7\u627f\u3002\u7531\u4e8e\u51fd\u6570\u90fd\u6709 prototype \u5c5e\u6027\uff08\u9664\u4e86 Function.prototype \u51fd\u6570\uff09\uff0c\u56e0\u6b64 A \u53ef\u4ee5\u662f\u4efb\u610f\u51fd\u6570\u3002<\/p>\n
\u9664\u4e86\u51fd\u6570\u4e4b\u5916\uff0cA \u7684\u503c\u8fd8\u53ef\u4ee5\u662f null\uff0c\u5f53 extend null<\/code> \u7684\u65f6\u5019\uff1a<\/p>\n
<\/p>\n
class<\/span> A<\/span> extends<\/span> null<\/span> {<\/span>\n}<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>A<\/span>.<\/span>__proto__<\/span> ===<\/span> Function<\/span>.<\/span>prototype<\/span>)<\/span>;<\/span> \/\/ true<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>A<\/span>.<\/span>prototype<\/span>.<\/span>__proto__<\/span> ===<\/span> undefined<\/span>)<\/span>;<\/span> \/\/ true<\/span><\/pre>\n<\/div>\n
Babel \u7f16\u8bd1<\/h2>\n
\u90a3 ES6 \u7684\u8fd9\u6bb5\u4ee3\u7801:<\/p>\n
<\/p>\n
class<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>name<\/span>)<\/span> {<\/span>\n        this<\/span>.<\/span>name<\/span> =<\/span> name<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\nclass<\/span> Child<\/span> extends<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n        super<\/span>(<\/span>name<\/span>)<\/span>;<\/span> \/\/ \u8c03\u7528\u7236\u7c7b\u7684 constructor(name)<\/span>\n        this<\/span>.<\/span>age<\/span> =<\/span> age<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\nvar<\/span> child1<\/span> =<\/span> new<\/span> Child<\/span>(<\/span>'kevin'<\/span>,<\/span> '18'<\/span>)<\/span>;<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>child1<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
Babel \u53c8\u662f\u5982\u4f55\u7f16\u8bd1\u7684\u5462\uff1f\u6211\u4eec\u53ef\u4ee5\u5728 Babel \u5b98\u7f51\u7684 Try it out <\/a> \u4e2d\u5c1d\u8bd5\uff1a<\/p>\n
<\/p>\n
'use strict'<\/span>;<\/span>\n\nfunction<\/span> _possibleConstructorReturn<\/span>(<\/span>self<\/span>,<\/span> call<\/span>)<\/span> {<\/span>\n    if<\/span> (<\/span>!<\/span>self<\/span>)<\/span> {<\/span>\n        throw<\/span> new<\/span> ReferenceError<\/span>(<\/span>\"this hasn't been initialised - super() hasn't been called\"<\/span>)<\/span>;<\/span>\n    }<\/span>\n    return<\/span> call<\/span> &&<\/span> (<\/span>typeof<\/span> call<\/span> ===<\/span> \"object\"<\/span> ||<\/span> typeof<\/span> call<\/span> ===<\/span> \"function\"<\/span>)<\/span> ? call<\/span> : self<\/span>;<\/span>\n}<\/span>\n\nfunction<\/span> _inherits<\/span>(<\/span>subClass<\/span>,<\/span> superClass<\/span>)<\/span> {<\/span>\n    if<\/span> (<\/span>typeof<\/span> superClass<\/span> !==<\/span> \"function\"<\/span> &&<\/span> superClass<\/span> !==<\/span> null<\/span>)<\/span> {<\/span>\n        throw<\/span> new<\/span> TypeError<\/span>(<\/span>\"Super expression must either be null or a function, not \"<\/span> +<\/span> typeof<\/span> superClass<\/span>)<\/span>;<\/span>\n    }<\/span>\n    subClass<\/span>.<\/span>prototype<\/span> =<\/span> Object<\/span>.<\/span>create<\/span>(<\/span>superClass<\/span> &&<\/span> superClass<\/span>.<\/span>prototype<\/span>,<\/span> {<\/span> constructor<\/span>: {<\/span> value<\/span>: subClass<\/span>,<\/span> enumerable<\/span>: false<\/span>,<\/span> writable<\/span>: true<\/span>,<\/span> configurable<\/span>: true<\/span> }<\/span> }<\/span>)<\/span>;<\/span>\n    if<\/span> (<\/span>superClass<\/span>)<\/span> Object<\/span>.<\/span>setPrototypeOf<\/span> ? Object<\/span>.<\/span>setPrototypeOf<\/span>(<\/span>subClass<\/span>,<\/span> superClass<\/span>)<\/span> : subClass<\/span>.<\/span>__proto__<\/span> =<\/span> superClass<\/span>;<\/span>\n}<\/span>\n\nfunction<\/span> _classCallCheck<\/span>(<\/span>instance<\/span>,<\/span> Constructor<\/span>)<\/span> {<\/span>\n    if<\/span> (<\/span>!<\/span>(<\/span>instance<\/span> instanceof<\/span> Constructor<\/span>)<\/span>)<\/span> {<\/span>\n        throw<\/span> new<\/span> TypeError<\/span>(<\/span>\"Cannot call a class as a function\"<\/span>)<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\nvar<\/span> Parent<\/span> =<\/span> function<\/span> Parent<\/span>(<\/span>name<\/span>)<\/span> {<\/span>\n    _classCallCheck<\/span>(<\/span>this<\/span>,<\/span> Parent<\/span>)<\/span>;<\/span>\n\n    this<\/span>.<\/span>name<\/span> =<\/span> name<\/span>;<\/span>\n}<\/span>;<\/span>\n\nvar<\/span> Child<\/span> =<\/span> function<\/span>(<\/span>_Parent<\/span>)<\/span> {<\/span>\n    _inherits<\/span>(<\/span>Child<\/span>,<\/span> _Parent<\/span>)<\/span>;<\/span>\n\n    function<\/span> Child<\/span>(<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n        _classCallCheck<\/span>(<\/span>this<\/span>,<\/span> Child<\/span>)<\/span>;<\/span>\n\n        \/\/ \u8c03\u7528\u7236\u7c7b\u7684 constructor(name)<\/span>\n        var<\/span> _this<\/span> =<\/span> _possibleConstructorReturn<\/span>(<\/span>this<\/span>,<\/span> (<\/span>Child<\/span>.<\/span>__proto__<\/span> ||<\/span> Object<\/span>.<\/span>getPrototypeOf<\/span>(<\/span>Child<\/span>)<\/span>)<\/span>.<\/span>call<\/span>(<\/span>this<\/span>,<\/span> name<\/span>)<\/span>)<\/span>;<\/span>\n\n        _this<\/span>.<\/span>age<\/span> =<\/span> age<\/span>;<\/span>\n        return<\/span> _this<\/span>;<\/span>\n    }<\/span>\n\n    return<\/span> Child<\/span>;<\/span>\n}<\/span>(<\/span>Parent<\/span>)<\/span>;<\/span>\n\nvar<\/span> child1<\/span> =<\/span> new<\/span> Child<\/span>(<\/span>'kevin'<\/span>,<\/span> '18'<\/span>)<\/span>;<\/span>\n\nconsole<\/span>.<\/span>log<\/span>(<\/span>child1<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u6211\u4eec\u53ef\u4ee5\u770b\u5230 Babel \u521b\u5efa\u4e86 _inherits \u51fd\u6570\u5e2e\u52a9\u5b9e\u73b0\u7ee7\u627f\uff0c\u53c8\u521b\u5efa\u4e86 _possibleConstructorReturn \u51fd\u6570\u5e2e\u52a9\u786e\u5b9a\u8c03\u7528\u7236\u7c7b\u6784\u9020\u51fd\u6570\u7684\u8fd4\u56de\u503c\uff0c\u6211\u4eec\u6765\u7ec6\u81f4\u7684\u770b\u4e00\u770b\u4ee3\u7801\u3002<\/p>\n
_inherits<\/h2>\n
<\/p>\n
function<\/span> _inherits<\/span>(<\/span>subClass<\/span>,<\/span> superClass<\/span>)<\/span> {<\/span>\n    \/\/ extend \u7684\u7ee7\u627f\u76ee\u6807\u5fc5\u987b\u662f\u51fd\u6570\u6216\u8005\u662f null<\/span>\n    if<\/span> (<\/span>typeof<\/span> superClass<\/span> !==<\/span> \"function\"<\/span> &&<\/span> superClass<\/span> !==<\/span> null<\/span>)<\/span> {<\/span>\n        throw<\/span> new<\/span> TypeError<\/span>(<\/span>\"Super expression must either be null or a function, not \"<\/span> +<\/span> typeof<\/span> superClass<\/span>)<\/span>;<\/span>\n    }<\/span>\n\n    \/\/ \u7c7b\u4f3c\u4e8e ES5 \u7684\u5bc4\u751f\u7ec4\u5408\u5f0f\u7ee7\u627f\uff0c\u4f7f\u7528 Object.create\uff0c\u8bbe\u7f6e\u5b50\u7c7b prototype \u5c5e\u6027\u7684 __proto__ \u5c5e\u6027\u6307\u5411\u7236\u7c7b\u7684 prototype \u5c5e\u6027<\/span>\n    subClass<\/span>.<\/span>prototype<\/span> =<\/span> Object<\/span>.<\/span>create<\/span>(<\/span>superClass<\/span> &&<\/span> superClass<\/span>.<\/span>prototype<\/span>,<\/span> {<\/span> constructor<\/span>: {<\/span> value<\/span>: subClass<\/span>,<\/span> enumerable<\/span>: false<\/span>,<\/span> writable<\/span>: true<\/span>,<\/span> configurable<\/span>: true<\/span> }<\/span> }<\/span>)<\/span>;<\/span>\n\n    \/\/ \u8bbe\u7f6e\u5b50\u7c7b\u7684 __proto__ \u5c5e\u6027\u6307\u5411\u7236\u7c7b<\/span>\n    if<\/span> (<\/span>superClass<\/span>)<\/span> Object<\/span>.<\/span>setPrototypeOf<\/span> ? Object<\/span>.<\/span>setPrototypeOf<\/span>(<\/span>subClass<\/span>,<\/span> superClass<\/span>)<\/span> : subClass<\/span>.<\/span>__proto__<\/span> =<\/span> superClass<\/span>;<\/span>\n}<\/span><\/pre>\n<\/div>\n
\u5173\u4e8e Object.create()\uff0c\u4e00\u822c\u6211\u4eec\u7528\u7684\u65f6\u5019\u4f1a\u4f20\u5165\u4e00\u4e2a\u53c2\u6570\uff0c\u5176\u5b9e\u662f\u652f\u6301\u4f20\u5165\u4e24\u4e2a\u53c2\u6570\u7684\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u8868\u793a\u8981\u6dfb\u52a0\u5230\u65b0\u521b\u5efa\u5bf9\u8c61\u7684\u5c5e\u6027\uff0c\u6ce8\u610f\u8fd9\u91cc\u662f\u7ed9\u65b0\u521b\u5efa\u7684\u5bf9\u8c61\u5373\u8fd4\u56de\u503c\u6dfb\u52a0\u5c5e\u6027\uff0c\u800c\u4e0d\u662f\u5728\u65b0\u521b\u5efa\u5bf9\u8c61\u7684\u539f\u578b\u5bf9\u8c61\u4e0a\u6dfb\u52a0\u3002<\/p>\n
\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
<\/p>\n
\/\/ \u521b\u5efa\u4e00\u4e2a\u4ee5\u53e6\u4e00\u4e2a\u7a7a\u5bf9\u8c61\u4e3a\u539f\u578b,\u4e14\u62e5\u6709\u4e00\u4e2a\u5c5e\u6027 p \u7684\u5bf9\u8c61<\/span>\nconst<\/span> o<\/span> =<\/span> Object<\/span>.<\/span>create<\/span>(<\/span>{<\/span>}<\/span>,<\/span> {<\/span> p<\/span>: {<\/span> value<\/span>: 42<\/span> }<\/span> }<\/span>)<\/span>;<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>o<\/span>)<\/span>;<\/span> \/\/ {p: 42}<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>o<\/span>.<\/span>p<\/span>)<\/span>;<\/span> \/\/ 42<\/span><\/pre>\n<\/div>\n
\u518d\u5b8c\u6574\u4e00\u70b9\uff1a<\/p>\n
<\/p>\n
const<\/span> o<\/span> =<\/span> Object<\/span>.<\/span>create<\/span>(<\/span>{<\/span>}<\/span>,<\/span> {<\/span>\n    p<\/span>: {<\/span>\n        value<\/span>: 42<\/span>,<\/span>\n        enumerable<\/span>: false<\/span>,<\/span>\n        \/\/ \u8be5\u5c5e\u6027\u4e0d\u53ef\u5199<\/span>\n        writable<\/span>: false<\/span>,<\/span>\n        configurable<\/span>: true<\/span>\n    }<\/span>\n}<\/span>)<\/span>;<\/span>\no<\/span>.<\/span>p<\/span> =<\/span> 24<\/span>;<\/span>\nconsole<\/span>.<\/span>log<\/span>(<\/span>o<\/span>.<\/span>p<\/span>)<\/span>;<\/span> \/\/ 42<\/span><\/pre>\n<\/div>\n
\u90a3\u4e48\u5bf9\u4e8e\u8fd9\u6bb5\u4ee3\u7801\uff1a<\/p>\n
\n
subClass<\/span>.<\/span>prototype<\/span> =<\/span> Object<\/span>.<\/span>create<\/span>(<\/span>superClass<\/span> &&<\/span> superClass<\/span>.<\/span>prototype<\/span>,<\/span> {<\/span> constructor<\/span>: {<\/span> value<\/span>: subClass<\/span>,<\/span> enumerable<\/span>: false<\/span>,<\/span> writable<\/span>: true<\/span>,<\/span> configurable<\/span>: true<\/span> }<\/span> }<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u4f5c\u7528\u5c31\u662f\u7ed9 subClass.prototype \u6dfb\u52a0\u4e00\u4e2a\u53ef\u914d\u7f6e\u53ef\u5199\u4e0d\u53ef\u679a\u4e3e\u7684 constructor \u5c5e\u6027\uff0c\u8be5\u5c5e\u6027\u503c\u4e3a subClass\u3002<\/p>\n
_possibleConstructorReturn<\/h2>\n
\u51fd\u6570\u91cc\u662f\u8fd9\u6837\u8c03\u7528\u7684\uff1a<\/p>\n
\n
var<\/span> _this<\/span> =<\/span> _possibleConstructorReturn<\/span>(<\/span>this<\/span>,<\/span> (<\/span>Child<\/span>.<\/span>__proto__<\/span> ||<\/span> Object<\/span>.<\/span>getPrototypeOf<\/span>(<\/span>Child<\/span>)<\/span>)<\/span>.<\/span>call<\/span>(<\/span>this<\/span>,<\/span> name<\/span>)<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u6211\u4eec\u7b80\u5316\u4e3a\uff1a<\/p>\n
\n
var<\/span> _this<\/span> =<\/span> _possibleConstructorReturn<\/span>(<\/span>this<\/span>,<\/span> Parent<\/span>.<\/span>call<\/span>(<\/span>this<\/span>,<\/span> name<\/span>)<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
_possibleConstructorReturn<\/code> \u7684\u6e90\u7801\u4e3a\uff1a<\/p>\n
<\/p>\n
function<\/span> _possibleConstructorReturn<\/span>(<\/span>self<\/span>,<\/span> call<\/span>)<\/span> {<\/span>\n    if<\/span> (<\/span>!<\/span>self<\/span>)<\/span> {<\/span>\n        throw<\/span> new<\/span> ReferenceError<\/span>(<\/span>\"this hasn't been initialised - super() hasn't been called\"<\/span>)<\/span>;<\/span>\n    }<\/span>\n    return<\/span> call<\/span> &&<\/span> (<\/span>typeof<\/span> call<\/span> ===<\/span> \"object\"<\/span> ||<\/span> typeof<\/span> call<\/span> ===<\/span> \"function\"<\/span>)<\/span> ? call<\/span> : self<\/span>;<\/span>\n}<\/span><\/pre>\n<\/div>\n
\u5728\u8fd9\u91cc\u6211\u4eec\u5224\u65ad Parent.call(this, name)<\/code> \u7684\u8fd4\u56de\u503c\u7684\u7c7b\u578b\uff0c\u54a6\uff1f\u8fd9\u4e2a\u503c\u8fd8\u80fd\u6709\u5f88\u591a\u7c7b\u578b\uff1f<\/p>\n
\u5bf9\u4e8e\u8fd9\u6837\u4e00\u4e2a class\uff1a<\/p>\n
<\/p>\n
class<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>)<\/span> {<\/span>\n        this<\/span>.<\/span>xxx<\/span> =<\/span> xxx<\/span>;<\/span>\n    }<\/span>\n}<\/span><\/pre>\n<\/div>\n
Parent.call(this, name) \u7684\u503c\u80af\u5b9a\u662f undefined\u3002\u53ef\u662f\u5982\u679c\u6211\u4eec\u5728 constructor \u51fd\u6570\u4e2d return \u4e86\u5462\uff1f\u6bd4\u5982\uff1a<\/p>\n
<\/p>\n
class<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>)<\/span> {<\/span>\n        return<\/span> {<\/span>\n            name<\/span>: 'kevin'<\/span>\n        }<\/span>\n    }<\/span>\n}<\/span><\/pre>\n<\/div>\n
\u6211\u4eec\u53ef\u4ee5\u8fd4\u56de\u5404\u79cd\u7c7b\u578b\u7684\u503c\uff0c\u751a\u81f3\u662f null\uff1a<\/p>\n
<\/p>\n
class<\/span> Parent<\/span> {<\/span>\n    constructor<\/span>(<\/span>)<\/span> {<\/span>\n        return<\/span> null<\/span>\n    }<\/span>\n}<\/span><\/pre>\n<\/div>\n
\u6211\u4eec\u63a5\u7740\u770b\u8fd9\u4e2a\u5224\u65ad\uff1a<\/p>\n
\n
call<\/span> &&<\/span> (<\/span>typeof<\/span> call<\/span> ===<\/span> \"object\"<\/span> ||<\/span> typeof<\/span> call<\/span> ===<\/span> \"function\"<\/span>)<\/span> ? call<\/span> : self<\/span>;<\/span><\/pre>\n<\/div>\n
\u6ce8\u610f\uff0c\u8fd9\u53e5\u8bdd\u7684\u610f\u601d\u5e76\u4e0d\u662f\u5224\u65ad call \u662f\u5426\u5b58\u5728\uff0c\u5982\u679c\u5b58\u5728\uff0c\u5c31\u6267\u884c (typeof call === \"object\" || typeof call === \"function\") ? call : self<\/code><\/p>\n
\u56e0\u4e3a &&<\/code> \u7684\u8fd0\u7b97\u7b26\u4f18\u5148\u7ea7\u9ad8\u4e8e ? :<\/code>\uff0c\u6240\u4ee5\u8fd9\u53e5\u8bdd\u7684\u610f\u601d\u5e94\u8be5\u662f\uff1a<\/p>\n
\n
(<\/span>call<\/span> &&<\/span> (<\/span>typeof<\/span> call<\/span> ===<\/span> \"object\"<\/span> ||<\/span> typeof<\/span> call<\/span> ===<\/span> \"function\"<\/span>)<\/span>)<\/span> ? call<\/span> : self<\/span>;<\/span><\/pre>\n<\/div>\n
\u5bf9\u4e8e Parent.call(this) \u7684\u503c\uff0c\u5982\u679c\u662f object \u7c7b\u578b\u6216\u8005\u662f function \u7c7b\u578b\uff0c\u5c31\u8fd4\u56de Parent.call(this)\uff0c\u5982\u679c\u662f null \u6216\u8005\u57fa\u672c\u7c7b\u578b\u7684\u503c\u6216\u8005\u662f undefined\uff0c\u90fd\u4f1a\u8fd4\u56de self \u4e5f\u5c31\u662f\u5b50\u7c7b\u7684 this\u3002<\/p>\n
\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u8fd9\u4e2a\u51fd\u6570\u88ab\u547d\u540d\u4e3a _possibleConstructorReturn<\/code>\u3002<\/p>\n
\u603b\u7ed3<\/h2>\n
<\/p>\n
var<\/span> Child<\/span> =<\/span> function<\/span>(<\/span>_Parent<\/span>)<\/span> {<\/span>\n    _inherits<\/span>(<\/span>Child<\/span>,<\/span> _Parent<\/span>)<\/span>;<\/span>\n\n    function<\/span> Child<\/span>(<\/span>name<\/span>,<\/span> age<\/span>)<\/span> {<\/span>\n        _classCallCheck<\/span>(<\/span>this<\/span>,<\/span> Child<\/span>)<\/span>;<\/span>\n\n        \/\/ \u8c03\u7528\u7236\u7c7b\u7684 constructor(name)<\/span>\n        var<\/span> _this<\/span> =<\/span> _possibleConstructorReturn<\/span>(<\/span>this<\/span>,<\/span> (<\/span>Child<\/span>.<\/span>__proto__<\/span> ||<\/span> Object<\/span>.<\/span>getPrototypeOf<\/span>(<\/span>Child<\/span>)<\/span>)<\/span>.<\/span>call<\/span>(<\/span>this<\/span>,<\/span> name<\/span>)<\/span>)<\/span>;<\/span>\n\n        _this<\/span>.<\/span>age<\/span> =<\/span> age<\/span>;<\/span>\n        return<\/span> _this<\/span>;<\/span>\n    }<\/span>\n\n    return<\/span> Child<\/span>;<\/span>\n}<\/span>(<\/span>Parent<\/span>)<\/span>;<\/span><\/pre>\n<\/div>\n
\u6700\u540e\u6211\u4eec\u603b\u4f53\u770b\u4e0b\u5982\u4f55\u5b9e\u73b0\u7ee7\u627f\uff1a<\/p>\n
\u9996\u5148\u6267\u884c _inherits(Child, Parent)<\/code>\uff0c\u5efa\u7acb Child \u548c Parent \u7684\u539f\u578b\u94fe\u5173\u7cfb\uff0c\u5373 Object.setPrototypeOf(Child.prototype, Parent.prototype)<\/code> \u548c Object.setPrototypeOf(Child, Parent)<\/code>\u3002<\/p>\n
\u7136\u540e\u8c03\u7528 Parent.call(this, name)<\/code>\uff0c\u6839\u636e Parent \u6784\u9020\u51fd\u6570\u7684\u8fd4\u56de\u503c\u7c7b\u578b\u786e\u5b9a\u5b50\u7c7b\u6784\u9020\u51fd\u6570 this \u7684\u521d\u59cb\u503c _this\u3002<\/p>\n
\u6700\u7ec8\uff0c\u6839\u636e\u5b50\u7c7b\u6784\u9020\u51fd\u6570\uff0c\u4fee\u6539 _this \u7684\u503c\uff0c\u7136\u540e\u8fd4\u56de\u8be5\u503c\u3002<\/p>\n
ES6 \u7cfb\u5217<\/h2>\n
ES6 \u7cfb\u5217\u76ee\u5f55\u5730\u5740\uff1ahttps:\/\/github.com\/mqyqingfeng\/Blog<\/a><\/p>\n
ES6 \u7cfb\u5217\u9884\u8ba1\u5199\u4e8c\u5341\u7bc7\u5de6\u53f3\uff0c\u65e8\u5728\u52a0\u6df1 ES6 \u90e8\u5206\u77e5\u8bc6\u70b9\u7684\u7406\u89e3\uff0c\u91cd\u70b9\u8bb2\u89e3\u5757\u7ea7\u4f5c\u7528\u57df\u3001\u6807\u7b7e\u6a21\u677f\u3001\u7bad\u5934\u51fd\u6570\u3001Symbol\u3001Set\u3001Map \u4ee5\u53ca Promise \u7684\u6a21\u62df\u5b9e\u73b0\u3001\u6a21\u5757\u52a0\u8f7d\u65b9\u6848\u3001\u5f02\u6b65\u5904\u7406\u7b49\u5185\u5bb9\u3002<\/p>\n<\/td>\n
\u6587\u7ae0\u8f6c\u8f7d\u81eahttps:\/\/github.com\/mqyqingfeng\/Blog\/issues\/106<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
\u524d\u8a00 \u5728\u4e0a\u4e00\u7bc7 \u300a ES6 \u7cfb\u5217 Babel \u662f\u5982\u4f55\u7f16\u8bd1 Class \u7684(\u4e0a)\u300b\uff0c\u6211\u4eec\u77e5\u9053\u4e86 Babel \u662f\u5982\u4f55\u7f16\u8bd1 Class \u7684\uff0c\u8fd9\u7bc7\u6211\u4eec\u5b66\u4e60 Babel …<\/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-1358","post","type-post","status-publish","format-standard","hentry","category-learn"],"_links":{"self":[{"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts\/1358"}],"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=1358"}],"version-history":[{"count":1,"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts\/1358\/revisions"}],"predecessor-version":[{"id":1455,"href":"https:\/\/www.lccc.top\/index.php?rest_route=\/wp\/v2\/posts\/1358\/revisions\/1455"}],"wp:attachment":[{"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lccc.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}