{"id":599,"date":"2025-12-07T10:13:07","date_gmt":"2025-12-07T02:13:07","guid":{"rendered":"https:\/\/www.52runoob.com\/?p=599"},"modified":"2025-12-07T10:13:07","modified_gmt":"2025-12-07T02:13:07","slug":"javascript%e4%b8%ad%e5%b0%86%e5%85%b6%e4%bb%96%e7%b1%bb%e5%9e%8b%e7%9a%84%e5%80%bc%e8%bd%ac%e6%8d%a2%e4%b8%ba%e5%ad%97%e7%ac%a6%e4%b8%b2%e7%9a%84%e6%96%b9%e6%b3%95%e5%8f%8a%e8%a7%84%e5%88%99%e8%af%a6","status":"publish","type":"post","link":"https:\/\/www.52runoob.com\/index.php\/2025\/12\/07\/javascript%e4%b8%ad%e5%b0%86%e5%85%b6%e4%bb%96%e7%b1%bb%e5%9e%8b%e7%9a%84%e5%80%bc%e8%bd%ac%e6%8d%a2%e4%b8%ba%e5%ad%97%e7%ac%a6%e4%b8%b2%e7%9a%84%e6%96%b9%e6%b3%95%e5%8f%8a%e8%a7%84%e5%88%99%e8%af%a6\/","title":{"rendered":"JavaScript\u4e2d\u5c06\u5176\u4ed6\u7c7b\u578b\u7684\u503c\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\u7684\u65b9\u6cd5\u53ca\u89c4\u5219\u8be6\u89e3"},"content":{"rendered":"\n

\u4e0b\u9762\u7ed9\u4f60\u4e00\u4efd JavaScript \u4e2d\u5c06\u5404\u79cd\u7c7b\u578b\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\u7684\u6240\u6709\u65b9\u6cd5 + \u5e95\u5c42\u89c4\u5219\u8be6\u89e3<\/strong>\uff0c\u6db5\u76d6 String()\u3001toString()\u3001\u6a21\u677f\u5b57\u7b26\u4e32\u3001\u9690\u5f0f\u8f6c\u6362\u3001Symbol\u3001\u5bf9\u8c61\u3001\u6570\u7ec4\u3001null\/undefined\u3001BigInt\u3001JSON<\/strong> \u7b49\u5168\u573a\u666f\u3002<\/p>\n\n\n\n

\u5185\u5bb9\u7ed3\u6784\u6e05\u6670\u3001\u53ef\u76f4\u63a5\u5f53\u7b14\u8bb0\u7528\u3002<\/p>\n\n\n\n

\n\n\n\n

\u2705 \u4e00\u3001JavaScript \u4e2d\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\u7684 5 \u5927\u65b9\u5f0f<\/h1>\n\n\n\n
\u65b9\u6cd5<\/th>\u662f\u5426\u5b89\u5168<\/th>\u9002\u7528\u7c7b\u578b<\/th>\u8bf4\u660e<\/th><\/tr><\/thead>
String(value)<\/strong><\/td>\u2714 \u5b89\u5168<\/td>\u6240\u6709\u7c7b\u578b<\/td>\u63a8\u8350\uff0c\u80fd\u5904\u7406 null \/ undefined<\/td><\/tr>
value.toString()<\/strong><\/td>\u2718 \u90e8\u5206\u7c7b\u578b\u4f1a\u62a5\u9519<\/td>null \/ undefined \u4f1a\u62a5\u9519<\/td>\u5bf9\u8c61\u53ef\u91cd\u5199<\/td><\/tr>
\u6a21\u677f\u5b57\u7b26\u4e32 ${value}<\/code><\/strong><\/td>\u2714 \u5b89\u5168<\/td>\u6240\u6709\u7c7b\u578b<\/td>\u5e38\u7528\u4e8e UI \u8f93\u51fa<\/td><\/tr>
\u9690\u5f0f\u8f6c\u6362\uff08value + ”\uff09<\/strong><\/td>\u2714 \u5b89\u5168<\/td>\u6240\u6709\u7c7b\u578b<\/td>\u89e6\u53d1 ToPrimitive<\/td><\/tr>
JSON.stringify(value)<\/strong><\/td>\u2714<\/td>\u6570\u7ec4\/\u5bf9\u8c61\u7b49<\/td>\u5e38\u7528\u4e8e\u5bf9\u8c61\u5e8f\u5217\u5316\uff0c\u4e0d\u7528\u4e8e\u901a\u7528\u8f6c\u6362<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\n

\u2705 \u4e8c\u3001\u5404\u79cd\u65b9\u5f0f\u7684\u8be6\u7ec6\u884c\u4e3a<\/h1>\n\n\n\n

1\ufe0f\u20e3 String(value)<\/strong> \u2014\u2014 \u6700\u63a8\u8350\u3001\u6700\u5b89\u5168<\/h2>\n\n\n
\nString(123)        \/\/ "123"\nString(true)       \/\/ "true"\nString(null)       \/\/ "null"\nString(undefined)  \/\/ "undefined"\nString(Symbol("x")) \/\/ "Symbol(x)"\n\n<\/pre><\/div>\n\n\n
\u2714 \u53ef\u4ee5\u5904\u7406 null \/ undefined<\/strong>\uff08\u4e0d\u4f1a\u62a5\u9519\uff09
\u2714 \u5185\u90e8\u8c03\u7528 ToString()<\/code> \u89c4\u8303\u8f6c\u6362
\u2714 \u5bf9\u8c61\u4f1a\u8c03\u7528\u5176 toString()<\/code> \u65b9\u6cd5<\/p>\n\n\n\n
\n\n\n\n
2\ufe0f\u20e3 value.toString()<\/strong> \u2014\u2014 \u4e0d\u5b89\u5168\uff0c\u4f46\u53ef\u63a7<\/h2>\n\n\n\n
\u274c \u4e24\u4e2a\u7c7b\u578b\u4f1a\u76f4\u63a5\u62a5\u9519<\/h3>\n\n\n
\nnull.toString()       \/\/ \u62a5\u9519\uff1aCannot read property 'toString'\nundefined.toString()  \/\/ \u62a5\u9519\n\n<\/pre><\/div>\n\n\n
\u2714 \u6570\u5b57\u3001\u5e03\u5c14\u503c\u6b63\u5e38<\/h3>\n\n\n
\n(123).toString() \/\/ "123"\ntrue.toString()  \/\/ "true"\n\n<\/pre><\/div>\n\n\n
\u2714 \u6570\u7ec4\u4e0e\u5bf9\u8c61<\/h3>\n\n\n
\n[1,2,3].toString()     \/\/ "1,2,3"\n({a:1}).toString()     \/\/ "[object Object]"\n\n<\/pre><\/div>\n\n\n
\u2714 Symbol<\/h3>\n\n\n
\nSymbol("x").toString() \/\/ "Symbol(x)"\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
3\ufe0f\u20e3 \u6a21\u677f\u5b57\u7b26\u4e32 ${value}<\/code><\/strong><\/h2>\n\n\n\n
\u5185\u90e8\u884c\u4e3a\u7b49\u540c\u4e8e\uff1a<\/p>\n\n\n
\nString(value)\n\n<\/pre><\/div>\n\n\n
\u793a\u4f8b\uff1a<\/p>\n\n\n
\n`${123}`       \/\/ "123"\n`${null}`      \/\/ "null"\n`${[1,2,3]}`   \/\/ "1,2,3"\n`${{a:1}}`     \/\/ "[object Object]"\n\n<\/pre><\/div>\n\n\n
\u2714 \u5b89\u5168
\u2714 \u63a8\u8350\u7528\u4e8e UI \u8f93\u51fa\uff08\u5982 Vue\/React \u6a21\u677f\uff09<\/p>\n\n\n\n
\n\n\n\n
4\ufe0f\u20e3 \u9690\u5f0f\u8f6c\u6362\uff08value + ”\uff09<\/strong><\/h2>\n\n\n\n
\u53ea\u8981\u9047\u5230\u5b57\u7b26\u4e32\u8fd0\u7b97\uff0c\u4f1a\u8bd5\u56fe\u628a\u5176\u4ed6\u7c7b\u578b\u53d8\u6210\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n
\n123 + ''      \/\/ "123"\ntrue + ''     \/\/ "true"\nnull + ''     \/\/ "null"\nundefined + '' \/\/ "undefined"\n\n<\/pre><\/div>\n\n\n
\u5e76\u4e14\uff1a
\u5bf9\u8c61 \u2192 ToPrimitive \u2192 toString \u2192 valueOf<\/strong><\/p>\n\n\n\n
\u793a\u4f8b\uff1a<\/p>\n\n\n
\n{} + '' \/\/ "[object Object]"\n\n<\/pre><\/div>\n\n\n
\u6570\u7ec4\uff1a<\/p>\n\n\n
\n[1,2,3] + ''   \/\/ "1,2,3"\n[] + ''        \/\/ ""\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
5\ufe0f\u20e3 JSON.stringify(value)<\/strong>\uff08\u4e0d\u662f\u901a\u7528\u8f6c\u6362\u51fd\u6570\uff09<\/h2>\n\n\n\n
\u5b83\u4e3b\u8981\u7528\u6765\u5c06\u5bf9\u8c61\u5e8f\u5217\u5316\uff1a<\/p>\n\n\n
\nJSON.stringify({a:1})  \/\/ '{"a":1}'\nJSON.stringify([1,2])  \/\/ "[1,2]"\n\n<\/pre><\/div>\n\n\n
\u4f46\u5b83\u4e5f\u80fd\u5904\u7406\u57fa\u7840\u7c7b\u578b\uff1a<\/p>\n\n\n
\nJSON.stringify(123)        \/\/ "123"\nJSON.stringify("abc")      \/\/ "\\"abc\\""\nJSON.stringify(null)       \/\/ "null"\n\n<\/pre><\/div>\n\n\n
\u2757 \u6ce8\u610f\u4e0d\u53ef\u5e8f\u5217\u5316\uff1a<\/h3>\n\n\n\n
\u503c<\/th>\u8f6c\u6362\u7ed3\u679c<\/th><\/tr><\/thead>
undefined<\/code><\/td>\u88ab\u5ffd\u7565\u6216\u53d8 null<\/td><\/tr>
function<\/code><\/td>\u88ab\u5ffd\u7565<\/td><\/tr>
Symbol<\/code><\/td>\u88ab\u5ffd\u7565<\/td><\/tr>
\u5faa\u73af\u5f15\u7528<\/code><\/td>\u62a5\u9519<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\n
\u2705 \u4e09\u3001\u5404\u79cd\u7c7b\u578b\u7684\u8f6c\u6362\u89c4\u5219\uff08\u6700\u5e95\u5c42 ToString \u89c4\u8303\uff09<\/h1>\n\n\n\n
\u2b50 Number \u2192 String<\/h2>\n\n\n\n
\u8f93\u5165<\/th>\u8f93\u51fa<\/th><\/tr><\/thead>
123<\/td>\"123\"<\/code><\/td><\/tr>
0<\/td>\"0\"<\/code><\/td><\/tr>
-0<\/td>\"0\"<\/code><\/td><\/tr>
NaN<\/td>\"NaN\"<\/code><\/td><\/tr>
Infinity<\/td>\"Infinity\"<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\n
\u2b50 Boolean \u2192 String<\/h2>\n\n\n
\ntrue \u2192 "true"\nfalse \u2192 "false"\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
\u2b50 null \/ undefined<\/h2>\n\n\n
\nString(null)        \/\/ "null"\nString(undefined)   \/\/ "undefined"\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
\u2b50 Symbol<\/h2>\n\n\n
\nString(Symbol("x")) \u2192 "Symbol(x)"\n\n<\/pre><\/div>\n\n\n
Symbol()<\/code> \u65e0\u6cd5\u9690\u5f0f\u8f6c\u6362\uff1a<\/p>\n\n\n
\nSymbol() + ''  \/\/ \u274c TypeError\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
\u2b50 BigInt<\/h2>\n\n\n
\nString(10n) \u2192 "10"\n\n<\/pre><\/div>\n\n\n
\u4f46 \u4e0d\u80fd\u9690\u5f0f\u8f6c\u6362<\/strong><\/p>\n\n\n
\n10n + ''  \/\/ \u274c TypeError: Cannot convert BigInt to string\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
\u2b50 Array \u2192 String<\/h2>\n\n\n\n
\u89c4\u5219\uff1a\u6bcf\u4e2a\u5143\u7d20\u8f6c\u4e3a\u5b57\u7b26\u4e32 \u2192 \u9017\u53f7\u62fc\u63a5<\/strong><\/p>\n\n\n
\n[1,2,3].toString()  \/\/ "1,2,3"\n[].toString()       \/\/ ""\n[null].toString()   \/\/ ""  \uff08null \u53d8\u6210\u7a7a\u5b57\u7b26\u4e32\uff09\n[undefined].toString()  \/\/ ""\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
\u2b50 Object \u2192 String<\/h2>\n\n\n\n
\u9ed8\u8ba4\u884c\u4e3a\uff1a<\/p>\n\n\n
\n({a:1}).toString()  \/\/ "[object Object]"\n\n<\/pre><\/div>\n\n\n
\u9664\u975e\u4f60\u91cd\u5199\uff1a<\/p>\n\n\n
\nconst obj = {\n  toString() { return "Hello"; }\n}\n\nString(obj) \/\/ "Hello"\n\n<\/pre><\/div>\n\n\n
\n\n\n\n
\u2705 \u56db\u3001\u63a8\u8350\u4f7f\u7528\u65b9\u5f0f\uff08\u9879\u76ee\u6700\u4f73\u5b9e\u8df5\uff09<\/h1>\n\n\n\n
\u573a\u666f<\/th>\u63a8\u8350\u65b9\u5f0f<\/th><\/tr><\/thead>
\u901a\u7528\u8f6c\u6362<\/td>\u2714 String(value)<\/code><\/td><\/tr>
UI \u5c55\u793a\uff08Vue\/React\uff09<\/td>\u2714 \u6a21\u677f\u5b57\u7b26\u4e32 ${value}<\/code><\/td><\/tr>
\u9700\u8981\u81ea\u5b9a\u4e49\u5bf9\u8c61\u8f93\u51fa<\/td>\u2714 \u81ea\u5df1\u5199 obj.toString()<\/code><\/td><\/tr>
\u5e8f\u5217\u5316\u4f20\u8f93\uff08API\uff09<\/td>\u2714 JSON.stringify<\/code><\/td><\/tr>
\u4ee3\u7801\u6027\u80fd\u8981\u6c42<\/td>\u2714 value + ''<\/code>\uff08\u6700\u5feb\uff09<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\n\n\n\n
\ud83c\udfaf \u603b\u7ed3\u8868\uff1a\u5404\u79cd\u7c7b\u578b\u7684\u8f6c\u6362\u7ed3\u679c<\/h1>\n\n\n\n
\u503c<\/th>String()<\/th>toString()<\/th>${}<\/code><\/th>+ ”<\/th>JSON.stringify<\/th><\/tr><\/thead>
123<\/td>“123”<\/td>“123”<\/td>“123”<\/td>“123”<\/td>“123”<\/td><\/tr>
true<\/td>“true”<\/td>“true”<\/td>“true”<\/td>“true”<\/td>“true”<\/td><\/tr>
null<\/td>“null”<\/td>\u274c\u62a5\u9519<\/td>“null”<\/td>“null”<\/td>“null”<\/td><\/tr>
undefined<\/td>“undefined”<\/td>\u274c\u62a5\u9519<\/td>“undefined”<\/td>“undefined”<\/td>undefined<\/td><\/tr>
Symbol(“x”)<\/td>“Symbol(x)”<\/td>“Symbol(x)”<\/td>“Symbol(x)”<\/td>\u274c\u62a5\u9519<\/td>undefined<\/td><\/tr>
10n<\/td>“10”<\/td>“10”<\/td>“10”<\/td>\u274c\u62a5\u9519<\/td>“10”<\/td><\/tr>
[1,2]<\/td>“1,2”<\/td>“1,2”<\/td>“1,2”<\/td>“1,2”<\/td>“[1,2]”<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"
\u4e0b\u9762\u7ed9\u4f60\u4e00\u4efd JavaScript \u4e2d\u5c06\u5404\u79cd\u7c7b\u578b\u8f6c\u6362\u4e3a\u5b57\u7b26\u4e32\u7684\u6240\u6709\u65b9\u6cd5 + \u5e95\u5c42… Continue Reading →<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[],"class_list":["post-599","post","type-post","status-publish","format-standard","hentry","category-javascript"],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/599","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/comments?post=599"}],"version-history":[{"count":1,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/599\/revisions"}],"predecessor-version":[{"id":600,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/599\/revisions\/600"}],"wp:attachment":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/media?parent=599"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/categories?post=599"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/tags?post=599"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}