{"id":296,"date":"2026-03-19T22:33:35","date_gmt":"2026-03-19T14:33:35","guid":{"rendered":"https:\/\/www.resilence.cn\/?p=296"},"modified":"2026-03-19T22:33:35","modified_gmt":"2026-03-19T14:33:35","slug":"day-26-%e5%bc%82%e6%ad%a5%e7%bc%96%e7%a8%8basync-await","status":"publish","type":"post","link":"https:\/\/www.resilence.cn\/?p=296","title":{"rendered":"Day-26-\u5f02\u6b65\u7f16\u7a0basync-await"},"content":{"rendered":"

Day 26: \u5f02\u6b65\u7f16\u7a0basync\/await<\/h1>\n
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\ud83d\udcc5 \u65e5\u671f: 2026\u5e7403\u670818\u65e5
\n\ud83c\udfaf \u5b66\u4e60\u76ee\u6807: \u6df1\u5165\u7406\u89e3 async\/await\uff0c\u638c\u63e1\u5f02\u6b65\u4ee3\u7801\u7684\u540c\u6b65\u5199\u6cd5
\n\u23f1\ufe0f \u9884\u8ba1\u7528\u65f6: 2-3 \u5c0f\u65f6
\n\ud83d\udcc2 \u5206\u7c7b: 10-\u73b0\u4ee3JavaScript<\/p>\n<\/blockquote>\n

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\ud83c\udfaf \u5b66\u4e60\u76ee\u6807<\/h2>\n

\u901a\u8fc7\u4eca\u5929\u7684\u5b66\u4e60\uff0c\u4f60\u5c06\uff1a<\/p>\n

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  1. \u7406\u89e3 async\/await \u8bed\u6cd5<\/strong>\uff1a\u8ba9\u5f02\u6b65\u4ee3\u7801\u770b\u8d77\u6765\u50cf\u540c\u6b65\u4ee3\u7801<\/li>\n
  2. \u638c\u63e1\u9519\u8bef\u5904\u7406<\/strong>\uff1atry\/catch\u3001\u5f02\u5e38\u4f20\u64ad<\/li>\n
  3. \u5b66\u4f1a\u5e76\u884c\u5904\u7406<\/strong>\uff1aPromise.all + async\/await<\/li>\n
  4. \u5b9e\u8df5\u6700\u4f73\u5b9e\u8df5<\/strong>\uff1a\u907f\u514d\u5e38\u89c1\u9677\u9631\u3001\u6027\u80fd\u4f18\u5316<\/li>\n
  5. \u5e94\u7528\u5b9e\u6218\u573a\u666f<\/strong>\uff1aAPI \u8bf7\u6c42\u3001\u6587\u4ef6\u64cd\u4f5c\u3001\u6570\u636e\u5e93\u67e5\u8be2<\/li>\n<\/ol>\n
    \n

    \ud83d\udca1 \u6838\u5fc3\u6982\u5ff5<\/h2>\n

    1. async \u51fd\u6570\u5b9a\u4e49<\/h3>\n
    \/\/ async \u51fd\u6570\u603b\u662f\u8fd4\u56de Promise\nasync function fetchUserData(userId) {\n    const response = await fetch('\/api\/users\/' + userId);\n    const user = await response.json();\n    return user;\n}\n\n\/\/ \u7b49\u4ef7\u4e8e\nfunction fetchUserData(userId) {\n    return fetch('\/api\/users\/' + userId)\n        .then(response => response.json());\n}\n<\/code><\/pre>\n
    2. await \u8868\u8fbe\u5f0f<\/h3>\n
    \/\/ await \u53ea\u80fd\u5728 async \u51fd\u6570\u4e2d\u4f7f\u7528\nasync function example() {\n    \/\/ \u6682\u505c\u6267\u884c\uff0c\u7b49\u5f85 Promise \u89e3\u51b3\n    const data = await fetchData();\n    console.log(data);\n    \n    \/\/ await \u540e\u7684\u4ee3\u7801\u4f1a\u5728 data \u51c6\u5907\u597d\u540e\u6267\u884c\n    console.log('\u7ee7\u7eed\u6267\u884c');\n}\n<\/code><\/pre>\n
    3. \u9519\u8bef\u5904\u7406<\/h3>\n
    \/\/ \u4f7f\u7528 try\/catch\nasync function handleError() {\n    try {\n        const data = await riskyOperation();\n        return { success: true, data };\n    } catch (error) {\n        console.error('\u9519\u8bef:', error);\n        return { success: false, error: error.message };\n    }\n}\n<\/code><\/pre>\n
    \n
    \ud83d\udee0\ufe0f API \u51fd\u6570\u8be6\u89e3<\/h2>\n
    1. async \u51fd\u6570<\/h3>\n
    \/\/ async \u51fd\u6570\u58f0\u660e\nasync function getData() {\n    const response = await fetch('\/api\/data');\n    const data = await response.json();\n    return data;\n}\n\n\/\/ async \u7bad\u5934\u51fd\u6570\nconst getUser = async (id) => {\n    const response = await fetch('\/api\/users\/' + id);\n    return await response.json();\n};\n\n\/\/ async \u65b9\u6cd5\nconst obj = {\n    async fetchData() {\n        return await fetch('\/api\/data');\n    }\n};\n<\/code><\/pre>\n
    2. await \u8868\u8fbe\u5f0f<\/h3>\n
    \/\/ await \u7b49\u5f85 Promise \u89e3\u51b3\nconst result = await promise;\n\n\/\/ \u53ef\u4ee5 await \u4efb\u4f55 thenable \u5bf9\u8c61\nconst thenable = {\n    then: (resolve) => resolve('value')\n};\nconst value = await thenable;\n\n\/\/ await \u7684\u4f18\u5148\u7ea7\u4f4e\u4e8e\u8fd0\u7b97\u7b26\nconst sum = await promise1 + await promise2;  \/\/ \u5e76\u884c\u6267\u884c\n<\/code><\/pre>\n
    3. \u9519\u8bef\u5904\u7406<\/h3>\n
    \/\/ try\/catch\/finally\nasync function withFinally() {\n    try {\n        await resource.acquire();\n        await doWork();\n    } catch (error) {\n        console.error(error);\n    } finally {\n        await resource.release();  \/\/ \u603b\u662f\u6267\u884c\n    }\n}\n\n\/\/ \u6355\u83b7\u7279\u5b9a\u7c7b\u578b\u7684\u9519\u8bef\nasync function specificCatch() {\n    try {\n        await riskyOperation();\n    } catch (error) {\n        if (error instanceof NetworkError) {\n            console.log('\u7f51\u7edc\u9519\u8bef');\n        } else if (error instanceof ValidationError) {\n            console.log('\u9a8c\u8bc1\u9519\u8bef');\n        } else {\n            throw error;  \/\/ \u91cd\u65b0\u629b\u51fa\n        }\n    }\n}\n<\/code><\/pre>\n
    \n
    \ud83c\udfae \u5b9e\u6218\u793a\u4f8b<\/h2>\n
    \u793a\u4f8b 1\uff1a\u987a\u5e8f\u6267\u884c\u5f02\u6b65\u64cd\u4f5c<\/h3>\n
    \/\/ \u4f7f\u7528 async\/await \u987a\u5e8f\u6267\u884c\nasync function getDashboardData() {\n    const user = await getUser(1);\n    const posts = await getPosts(user.id);\n    const comments = await getComments(posts[0].id);\n    \n    return { user, posts, comments };\n}\n\n\/\/ \u76f8\u6bd4 then \u94fe\nfunction getDashboardDataOld() {\n    return getUser(1)\n        .then(user => getPosts(user.id))\n        .then(posts => getComments(posts[0].id));\n}\n<\/code><\/pre>\n
    \u793a\u4f8b 2\uff1a\u5e76\u884c\u6267\u884c\u5f02\u6b65\u64cd\u4f5c<\/h3>\n
    \/\/ \u5e76\u884c\u6267\u884c\u591a\u4e2a\u72ec\u7acb\u7684\u5f02\u6b65\u64cd\u4f5c\nasync function fetchAllData() {\n    const [users, posts, comments] = await Promise.all([\n        fetch('\/api\/users').then(r => r.json()),\n        fetch('\/api\/posts').then(r => r.json()),\n        fetch('\/api\/comments').then(r => r.json())\n    ]);\n    \n    return { users, posts, comments };\n}\n\n\/\/ \u4f7f\u7528 for...of \u5faa\u73af\nasync function fetchAllItems(urls) {\n    const results = [];\n    for (const url of urls) {\n        const response = await fetch(url);\n        const data = await response.json();\n        results.push(data);\n    }\n    return results;\n}\n<\/code><\/pre>\n
    \u793a\u4f8b 3\uff1a\u8d85\u65f6\u63a7\u5236<\/h3>\n
    \/\/ Promise.race + async\/await\nasync function fetchWithTimeout(url, timeout = 5000) {\n    const controller = new AbortController();\n    \n    const timeoutPromise = new Promise((_, reject) => {\n        setTimeout(() => {\n            controller.abort();\n            reject(new Error('\u8bf7\u6c42\u8d85\u65f6'));\n        }, timeout);\n    });\n    \n    try {\n        const response = await fetch(url, {\n            signal: controller.signal\n        });\n        return await response.json();\n    } catch (error) {\n        if (error.name === 'AbortError') {\n            throw new Error('\u8bf7\u6c42\u8d85\u65f6');\n        }\n        throw error;\n    }\n}\n<\/code><\/pre>\n
    \n
    \u26a0\ufe0f \u91cd\u8981\u6ce8\u610f\u4e8b\u9879<\/h2>\n
    1. async \u51fd\u6570\u603b\u662f\u8fd4\u56de Promise<\/h3>\n
    \/\/ \u6b63\u786e\uff1a\u53ef\u4ee5\u5229\u7528\u8fd4\u56de\u503c\nconst promise = async function() {\n    return 'value';\n};  \/\/ \u8fd4\u56de Promise\n\n\/\/ \u9519\u8bef\uff1a\u5fd8\u8bb0 await\nasync function wrong() {\n    const result = getData();  \/\/ \u5fc5\u987b\u52a0 await\uff01\n    console.log(result);  \/\/ \u8f93\u51fa Promise \u5bf9\u8c61\n}\n<\/code><\/pre>\n
    2. await \u53ea\u80fd\u5728 async \u51fd\u6570\u4e2d\u4f7f\u7528<\/h3>\n
    \/\/ \u6b63\u786e\uff1a\u5728 async \u51fd\u6570\u4e2d\u4f7f\u7528 await\nasync function correct() {\n    const data = await fetchData();\n    return data;\n}\n\n\/\/ \u9519\u8bef\uff1a\u5728\u975e async \u51fd\u6570\u4e2d\u4f7f\u7528 await\nfunction wrong() {\n    const data = await fetchData();  \/\/ SyntaxError!\n    return data;\n}\n<\/code><\/pre>\n
    3. \u907f\u514d Promise \u6784\u9020\u5668\u53cd\u6a21\u5f0f<\/h3>\n
    \/\/ \u274c \u9519\u8bef\uff1aPromise \u6784\u9020\u5668\u53cd\u6a21\u5f0f\nasync function wrong() {\n    return new Promise((resolve, reject) => {\n        const data = await fetchData();\n        resolve(data);\n    });\n}\n\n\/\/ \u2705 \u6b63\u786e\uff1a\u76f4\u63a5 await\nasync function correct() {\n    const data = await fetchData();\n    return data;\n}\n<\/code><\/pre>\n
    4. \u5e76\u884c\u6267\u884c\u6280\u5de7<\/h3>\n
    \/\/ \u4f7f\u7528 Promise.all \u5e76\u884c\nasync function parallel() {\n    const [result1, result2] = await Promise.all([\n        operation1(),\n        operation2()\n    ]);\n}\n\n\/\/ \u4f7f\u7528 for...of \u5e76\u884c\nasync function parallelLoop(items) {\n    const promises = items.map(item => processItem(item));\n    const results = await Promise.all(promises);\n    return results;\n}\n<\/code><\/pre>\n
    \n
    \ud83c\udf93 \u5b9e\u6218\u5e94\u7528\u573a\u666f<\/h2>\n
    \u573a\u666f 1: API \u8bf7\u6c42<\/h3>\n
    \/\/ \u83b7\u53d6\u7528\u6237\u5b8c\u6574\u4fe1\u606f\nasync function getUserInfo(userId) {\n    try {\n        const [profile, posts, friends] = await Promise.all([\n            fetch('\/api\/users\/' + userId + '\/profile').then(r => r.json()),\n            fetch('\/api\/users\/' + userId + '\/posts').then(r => r.json()),\n            fetch('\/api\/users\/' + userId + '\/friends').then(r => r.json())\n        ]);\n        \n        return {\n            profile,\n            posts,\n            friends\n        };\n    } catch (error) {\n        console.error('\u83b7\u53d6\u7528\u6237\u4fe1\u606f\u5931\u8d25:', error);\n        throw error;\n    }\n}\n<\/code><\/pre>\n
    \u573a\u666f 2: \u6587\u4ef6\u64cd\u4f5c<\/h3>\n
    \/\/ \u8bfb\u53d6\u591a\u4e2a\u6587\u4ef6\nasync function loadConfigFiles() {\n    const [config1, config2, config3] = await Promise.all([\n    readFile('.\/config1.json').then(JSON.parse),\n    readFile('.\/config2.json').then(JSON.parse),\n    readFile('.\/config3.json').then(JSON.parse)\n    ]);\n    \n    return { config1, config2, config3 };\n}\n\n\/\/ \u987a\u5e8f\u5904\u7406\u6587\u4ef6\nasync function processFiles(files) {\n    for (const file of files) {\n        const data = await readFile(file);\n        await processFile(data);\n        await writeFile('processed\/' + file, data);\n    }\n}\n<\/code><\/pre>\n
    \u573a\u666f 3: \u6570\u636e\u5e93\u67e5\u8be2<\/h3>\n
    \/\/ \u8fde\u63a5\u6c60\u67e5\u8be2\nasync function getUserWithPosts(userId) {\n    const client = await pool.connect();\n    \n    try {\n        const user = await client.query(\n            'SELECT * FROM users WHERE id = $1',\n            [userId]\n        );\n        \n        if (!user) {\n            throw new Error('\u7528\u6237\u4e0d\u5b58\u5728');\n        }\n        \n        const posts = await client.query(\n            'SELECT * FROM posts WHERE user_id = $1 ORDER BY created_at DESC',\n            [userId]\n        );\n        \n        return { ...user, posts };\n    } finally {\n        client.release();\n    }\n}\n<\/code><\/pre>\n
    \n
    \u270d\ufe0f \u7ec3\u4e60\u4efb\u52a1<\/h2>\n
    \u57fa\u7840\u7ec3\u4e60\uff08\u5fc5\u505a\uff09<\/h3>\n
      \n
    1. \n
      async\/await \u8f6c\u6362<\/strong>\uff1a<\/p>\n