无法将字符串推入数组

Question

我正在尝试学习 EJS 并制作博客，但我似乎无法理解这个错误

我想做的是尝试将一些数据库响应作为对象写入数组，然后将其推送到文件。我正在使用 replit DB

const fs = require("fs")
const Database = require("@replit/database")
const db = new Database()

exports.load = async function(){
  db.set("hello", {
    "author": "Some author 1",
    "title": "Blog Post 1",
    "content": "First post content",
    "date_posted": "Dec 17, 2021"
  })

  var posts = new Array()

  db.list().then(keys => {
    keys.forEach(key => {
      posts.push(`      <article class="media content-section">
        <div class="media-body">
          <div class="article-metadata">
            <a class="mr-2" href="/p">Anonymous</a>
            <small class="text-muted">${db.get(key).date_posted}</small>
          </div>
          <h2><a class="article-title" href="#">${ db.get(key).title }</a></h2>
          <p class="article-content">${ db.get(key).content }</p>
        </div>
      </article`
      )
    })
  });

  posts = posts.join()

  fs.writeFileSync("public/posts.ejs", posts)
}

我在运行代码时遇到的错误：

UnhandledPromiseRejectionWarning: TypeError: posts.push is not a function

Answer 1

首先，您声明var posts = new Array()。所以 posts 是一个数组。下一行（按执行顺序）：posts = posts.join()。所以现在 posts 是一个空字符串。您正在更改变量的类型，这是一种不好的做法（Typescript 不允许您这样做）。现在执行顺序的下一行：.then(keys =>。您开始将内容推入 posts，但是 posts 现在是一个字符串，还记得吗？不再是数组。

您无缘无故地使用了 async 关键字，因为其中没有 await。您不妨利用它：

exports.load = async function(){
  db.set("hello", {
    "author": "Some author 1",
    "title": "Blog Post 1",
    "content": "First post content",
    "date_posted": "Dec 17, 2021"
  })

  let postsArray = new Array();

  const keys = await db.list();

  keys.forEach(key => {
    postsArray.push(`<article class="media content-section">
      <div class="media-body">
        <div class="article-metadata">
          <a class="mr-2" href="/p">Anonymous</a>
          <small class="text-muted">${db.get(key).date_posted}</small>
        </div>
        <h2><a class="article-title" href="#">${ db.get(key).title }</a></h2>
        <p class="article-content">${ db.get(key).content }</p>
      </div>
    </article`
    )
  })
  
  const posts = postsArray.join()

  fs.writeFileSync("public/posts.ejs", posts)
}

或在一行中使用 .map() ：

exports.load = async function(){
  db.set("hello", {
    "author": "Some author 1",
    "title": "Blog Post 1",
    "content": "First post content",
    "date_posted": "Dec 17, 2021"
  })

  const keys = await db.list();

  const posts = keys.map( key => `<article class="media content-section">....</article`).join();

  fs.writeFileSync("public/posts.ejs", posts)
}

无法将字符串推入数组

Unable to push string into array

javascript

arrays

ejs

node.js