docs__myblog__js__01.md.js

(window["webpackJsonp"]=window["webpackJsonp"]||[]).push([[71],{zFvF:function(e,n,l){"use strict";l.r(n);var t=l("q1tI"),a=l.n(t),r=l("dEAq"),c=l("H1Ra"),o=a.a.memo((e=>{e.demos;return a.a.createElement(a.a.Fragment,null,a.a.createElement("div",{className:"markdown"},a.a.createElement("h1",{id:"js-\u88c5\u7bb1\u548c\u62c6\u7bb1"},a.a.createElement(r["AnchorLink"],{to:"#js-\u88c5\u7bb1\u548c\u62c6\u7bb1","aria-hidden":"true",tabIndex:-1},a.a.createElement("span",{className:"icon icon-link"})),"JS \u88c5\u7bb1\u548c\u62c6\u7bb1"),a.a.createElement("p",null,"\u6709\u8fd9\u6837\u7684\u4e00\u4e2a\u9762\u8bd5\u9898\uff1a"),a.a.createElement(c["a"],{code:"var s = '\u4f60\u597d';\nconsole.log(typeof s); //string\nconsole.log(s instanceof String); // false",lang:"js"}),a.a.createElement("p",null,"\u7b54\u6848\u662f\u4ec0\u4e48\u5462\uff1f\u4e00\u822c\u4eba\u90fd\u4f1a\u56de\u7b54\u7b2c\u4e00\u4e2a\u662f",a.a.createElement("code",null,"string"),",\u7b2c\u4e8c\u4e2a\u662f ",a.a.createElement("code",null,"true"),",\u4f46\u662f\u8fd9\u4e2a\u7b54\u6848\u662f\u9519\u8bef\u7684\uff0c\u7b2c\u4e00\u4e2a\u662f",a.a.createElement("code",null,"string"),"\u6ca1\u9519\uff0c\u4f46\u662f\u7b2c\u4e8c\u4e2a\u4e0d\u662f",a.a.createElement("code",null,"true"),"\u800c\u662f",a.a.createElement("code",null,"false"),",\u4e3a\u4ec0\u4e48\u5462\uff1f\uff0c\u6709\u4eba\u4f1a\u95ee\u90a3\u4e0d\u90fd\u662f",a.a.createElement("code",null,"string"),"\u7c7b\u578b\u5417?,\u6709\u4eba\u8bf4\u56e0\u4e3a\u4e0d\u662f",a.a.createElement("code",null,"new"),"\u51fa\u6765\u7684\uff0c\u90a3\u4e3a\u4ec0\u4e48\u53ef\u4ee5\u4f7f\u7528",a.a.createElement("code",null,"length"),"\u7684\u65b9\u6cd5\u5462\uff1f\u5176\u5b9e\u662f\u7528\u5230\u4e86",a.a.createElement("code",null,"javascript"),"\u88c5\u7bb1\u548c\u62c6\u7bb1\u7684\u65b9\u6cd5\u3002"),a.a.createElement("p",null,"\u4e0b\u9762\u6211\u4eec\u4e00\u8d77\u6765\u63a2\u7d22\u4e00\u4e0b javascript \u7684",a.a.createElement("strong",null,"\u88c5\u7bb1"),"\u548c",a.a.createElement("strong",null,"\u62c6\u7bb1"),"\u662f\u4ec0\u4e48\uff1f"),a.a.createElement("h2",{id:"\u88c5\u7bb1\u662f\u4ec0\u4e48"},a.a.createElement(r["AnchorLink"],{to:"#\u88c5\u7bb1\u662f\u4ec0\u4e48","aria-hidden":"true",tabIndex:-1},a.a.createElement("span",{className:"icon icon-link"})),a.a.createElement("strong",null,"\u88c5\u7bb1\u662f\u4ec0\u4e48\uff1f")),a.a.createElement("p",null,a.a.createElement("code",null,"s"),"\u4e3a\u4ec0\u4e48\u4e0d\u662f",a.a.createElement("code",null,"String"),"\u5374\u80fd\u4f7f\u7528",a.a.createElement("code",null,"String"),"\u7684\u65b9\u6cd5\u5462\uff1f"),a.a.createElement("p",null,"\u88c5\u7bb1\uff1a\u662f\u6307\u5c06\u57fa\u672c\u6570\u636e\u7c7b\u578b\u8f6c\u6362\u4e3a\u5bf9\u5e94\u7684\u5f15\u7528\u7c7b\u578b\u7684\u64cd\u4f5c\uff0c\u800c\u88c5\u7bb1\u53c8\u5206\u4e3a",a.a.createElement("strong",null,"\u9690\u5f0f\u88c5\u7bb1"),"\u548c",a.a.createElement("strong",null,"\u663e\u5f0f\u88c5\u7bb1"),"\u3002"),a.a.createElement("ul",null,a.a.createElement("li",null,a.a.createElement("p",null,"\u9690\u5f0f\u88c5\u7bb1"),a.a.createElement("p",null,"\u5f53\u8bfb\u53d6\u4e00\u4e2a\u57fa\u672c\u7c7b\u578b\u503c\u65f6\uff0c\u540e\u53f0\u4f1a\u521b\u5efa\u4e00\u4e2a\u8be5\u57fa\u672c\u7c7b\u578b\u6240\u5bf9\u5e94\u7684\u57fa\u672c\u5305\u88c5\u7c7b\u578b\u5bf9\u8c61\u3002\u5728\u8fd9\u4e2a\u57fa\u672c\u7c7b\u578b\u7684\u5bf9\u8c61\u4e0a\u8c03\u7528\u65b9\u6cd5\uff0c\u5176\u5b9e\u5c31\u662f\u5728\u8fd9\u4e2a\u57fa\u672c\u7c7b\u578b\u5bf9\u8c61\u4e0a\u8c03\u7528\u65b9\u6cd5\u3002\u8fd9\u4e2a\u57fa\u672c\u7c7b\u578b\u7684\u5bf9\u8c61\u662f\u4e34\u65f6\u7684\uff0c\u5b83\u53ea\u5b58\u5728\u4e8e\u65b9\u6cd5\u8c03\u7528\u90a3\u4e00\u884c\u4ee3\u7801\u6267\u884c\u7684\u77ac\u95f4\uff0c\u6267\u884c\u65b9\u6cd5\u540e\u7acb\u5373\u88ab\u9500\u6bc1\u3002\u8fd9\u4e5f\u662f\u5728\u57fa\u672c\u7c7b\u578b\u4e0a\u6dfb\u52a0\u5c5e\u6027\u548c\u65b9\u6cd5\u4f1a\u4e0d\u8bc6\u522b\u6216\u62a5\u9519\u7684\u539f\u56e0\u4e86"),a.a.createElement("p",null,"\u5bf9\u4e8e\u9690\u5f0f\u88c5\u7bb1\uff0c\u53ef\u4ee5\u770b\u4e0b\u9762\u7684\u4ee3\u7801"),a.a.createElement(c["a"],{code:"var s1 = '1233'; // \u9690\u5f0f\u88c5\u7bb1\nvar s2 = s1.substring(2);\n\n//\u76f8\u5f53\u4e8e\u4e0b\u9762\u7684\u6b65\u9aa4\n// 1.\u521b\u5efa\u4e00\u4e2a Number \u7c7b\u578b\u7684\u5b9e\u4f8b\u3002\n// 2.\u5728\u5b9e\u4f8b\u4e0a\u8c03\u7528\u65b9\u6cd5\u3002\n// 3.\u9500\u6bc1\u5b9e\u4f8b\nvar s1 = new String('1233');\nvar s2 = s1.substring(2);\ns1 = null;",lang:"js"}),a.a.createElement("p",null,"\u9690\u5f0f\u88c5\u4fee\u5f53\u8bfb\u53d6\u4e00\u4e2a\u57fa\u672c\u7c7b\u578b\u503c\u65f6\uff0c\u540e\u53f0\u4f1a\u521b\u5efa\u4e00\u4e2a\u8be5\u57fa\u672c\u7c7b\u578b\u7684\u6240\u5bf9\u5e94\u57fa\u672c\u5305\u88c5\u7c7b\u578b\u5bf9\u8c61\uff0c\u5728\u8fd9\u4e2a\u57fa\u672c\u7c7b\u578b\u7684\u5bf9\u8c61\u4e0a\u8c03\u7528\u65b9\u6cd5\uff0c\u5176\u5b9e\u5c31\u662f\u5728\u8fd9\u4e2a\u57fa\u672c\u7c7b\u578b\u5bf9\u8c61\u4e0a\u8c03\u7528\u65b9\u6cd5\uff0c\u8fd9\u4e2a\u57fa\u672c\u7c7b\u578b\u7684\u5bf9\u8c61\u662f\u4e34\u65f6\u7684\uff0c\u5854\u5b50\u5b58\u5728\u4e8e\u65b9\u6cd5\u8c03\u7528\u90a3\u4e00\u884c\u4ee3\u7801\u6267\u884c\u7684\u77ac\u95f4\uff0c\u6267\u884c\u4e4b\u540e\u7acb\u5373\u9500\u6bc1\uff0c\u8fd9\u4e5f\u5c31\u662f\u57fa\u672c\u7c7b\u578b\u4e0a\u6dfb\u52a0\u5c5e\u6027\u548c\u65b9\u6cd5\u4e0d\u5bf9\u8bc6\u522b\u548c\u62a5\u9519\u7684\u539f\u56e0\u4e86\u3002")),a.a.createElement("li",null,a.a.createElement("p",null,"\u663e\u793a\u88c5\u7bb1"),a.a.createElement("p",null,"\u8fd9\u662f\u901a\u8fc7\u57fa\u672c\u5305\u88c5\u7c7b\u578b\u5bf9\u8c61\u5bf9\u57fa\u672c\u7c7b\u578b\u8fdb\u884c\u663e\u793a\u88c5\u7bb1"),a.a.createElement(c["a"],{code:"var s1 = new String('1233');",lang:"js"}),a.a.createElement("p",null,"\u663e\u793a\u88c5\u7bb1\u7684\u64cd\u7eb5\u53ef\u4ee5\u5bf9",a.a.createElement("code",null,"new"),"\u51fa\u6765\u7684\u5bf9\u8c61\u8fdb\u884c\u5c5e\u6027\u548c\u65b9\u6cd5\u7684\u6dfb\u52a0\u5566\uff0c\u56e0\u4e3a\u901a\u8fc7\u901a\u8fc7",a.a.createElement("code",null,"new"),"\u64cd\u4f5c\u7b26\u521b\u5efa\u7684\u5f15\u7528\u7c7b\u578b\u7684\u5b9e\u4f8b\uff0c\u5728\u6267\u884c\u6d41\u79bb\u5f00\u5f53\u524d\u4f5c\u7528\u57df\u4e4b\u524d\u4e00\u76f4\u4fdd\u7559\u5728\u5185\u5b58\u4e2d,"),a.a.createElement("p",null,"\u4f8b\u5982\uff1a"),a.a.createElement(c["a"],{code:"var s1 = new String('1233');\ns1.a = function() {\n  console.log(111);\n};\ns1.name = '\u6211\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32';\nconsole.log(s1.name); //'\u6211\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32'\ns1.a(); //111",lang:"js"}))),a.a.createElement("h2",{id:"\u62c6\u7bb1\u662f\u4ec0\u4e48"},a.a.createElement(r["AnchorLink"],{to:"#\u62c6\u7bb1\u662f\u4ec0\u4e48","aria-hidden":"true",tabIndex:-1},a.a.createElement("span",{className:"icon icon-link"})),a.a.createElement("strong",null,"\u62c6\u7bb1\u662f\u4ec0\u4e48\uff1f")),a.a.createElement("p",null,"\u62c6\u7bb1\u662f\u6307\u628a\u5f15\u7528\u7c7b\u578b\u8f6c\u6362\u6210\u57fa\u672c\u7684\u6570\u636e\u7c7b\u578b\u3002\u901a\u5e38\u901a\u8fc7\u5f15\u7528\u7c7b\u578b\u7684",a.a.createElement("code",null,"valueOf()"),"\u548c",a.a.createElement("code",null,"toString()"),"\u65b9\u6cd5\u6765\u5b9e\u73b0"),a.a.createElement(c["a"],{code:"var objNum = new Number(64);\nvar objStr = new String('64');\nconsole.log(typeof objNum); // object\nconsole.log(typeof objStr); // object\n//\u62c6\u7bb1\nconsole.log(typeof objNum.valueOf()); // number \u57fa\u672c\u7684\u6570\u5b57\u7c7b\u578b\uff0c\u60f3\u8981\u7684\nconsole.log(typeof objNum.toString()); // string \u57fa\u672c\u7684\u5b57\u7b26\u7c7b\u578b\uff0c\u4e0d\u60f3\u8981\u7684\nconsole.log(typeof objStr.valueOf()); // string \u57fa\u672c\u7684\u6570\u636e\u7c7b\u578b\uff0c\u4e0d\u60f3\u8981\u7684\nconsole.log(typeof objStr.toString()); // string \u57fa\u672c\u7684\u6570\u636e\u7c7b\u578b\uff0c\u60f3\u8981\u7684",lang:"js"}),a.a.createElement("p",null,"\u6240\u4ee5\u62c6\u7bb1\u4e5f\u8981\u6839\u636e\u5b9e\u9645\u60c5\u51b5\u6765\u62c6\u7bb1")))}));n["default"]=e=>{var n=a.a.useContext(r["context"]),l=n.demos;return a.a.useEffect((()=>{var n;null!==e&&void 0!==e&&null!==(n=e.location)&&void 0!==n&&n.hash&&r["AnchorLink"].scrollToAnchor(decodeURIComponent(e.location.hash.slice(1)))}),[]),a.a.createElement(o,{demos:l})}}}]);