Node.js批量转换Markdown为JSON时输出标准数组格式问题

本人具备C++开发基础，目前正在学习JavaScript，正在开发一款实用工具，可接收.md（Markdown）文件，将其解析转换为HTML后生成JSON对象，最终按照指定格式写入已存在的JSON文件中。

工具的完整处理流水线如下：

• 遍历Markdown文件目录 -> 逐文件执行解析转换，将Markdown内容转为HTML -> 将HTML内容与解析得到的元数据写入JSON文件

说明：目前大部分逻辑已开发完成，仅存在JSON格式相关问题需要协助，请完整阅读问题内容后再作答，感谢！

流水线核心逻辑 #

export function transformMdtoHtmltoJson(dest, post) {
    
    const file = matter.read(post);
    
    const title = file.data.title;
    const date = file.data.date;
    const description = file.data.description;
    const socials = file.data.socials;
    
    unified()
        .use(remarkParse)
        .use(remarkRehype)
        .use(rehypeStringify)
        .process(file.content)
        .then(
            (result) => {
                toJson(dest, title, date, description, result.value, socials);
            },
            (err) => {
                throw err;
            }
          );
}

JSON文件写入模块 #

class Data {

  constructor(title, date, description, content, socials) {
    this.title = title;
    this.date = date;
    this.description = description;
    this.content = content;
    this.socials = socials;
  }
}


function createNewMember(title, date, description, content, socials) {
        let newMemer = new Data(title, date, description, content, socials);
        let result = {};
        return result = {
                "title": newMemer.title,
                "date": newMemer.date,
                "description": newMemer.description,
                "content": newMemer.content,
                "socials": newMemer.socials
        }
}

export async function toJson(inFile, title, data, description, content, socials) {
  const rl = readline.createInterface({
    input: fs.createReadStream(inFile),
    crlfDelay: Infinity,
  });
  const lines = [];
  for await (const line of rl) {
    lines.push(line);
  }
  let object = createNewMember(title, data, description, content, socials);
  lines.push(JSON.stringify(object));
  let string = lines.join('') + ',';
  writeFile(inFile, string);
}

function writeFile(inFile, data) {
          fs.writeFile(inFile, data, { flag: "a+" }, (err) => {
                            if (err) throw err;
                            console.log("The file has been saved!");
                          }
                          );
}

posts目录下存放待处理的Markdown文件，路径分别为：

• ~/path/to/posts/post1.md
• ~/path/to/posts/post2.md
• ~/path/to/posts/post3.md

为简化测试，三个Markdown文件内容完全一致，如下：

---
title: Hello this is a test
date: 05/04/2022
description: this is a test
socials:
---

# Hello
## subhello

目标输出文件路径为~/path/to/post.json，入口执行函数代码如下：

const postDir = path.join(process.cwd(), 'posts');
const destDir = path.join(process.cwd(), '_data');
const jsonFile = 'post.json';

const fileNames = fs.readdirSync(postDir);

async function generatePosts(fileNames, postDir, destDir, jsonFile) {
          fileNames.forEach( (fileName) => {
                        const fullPath = path.join(postDir, fileName);
                        const destPath = path.join(destDir, jsonFile)
                        transformMdtoHtmltoJson(destPath, fullPath);
                });
}


generatePosts(fileNames, postDir, destDir, jsonFile);

当前运行得到的post.json输出为多个并列的JSON对象，无外层数组包裹，内容如下：

{
"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null},
{
"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null},
{"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null
},

期望实现的效果是将所有输出的JSON对象用[]包裹，组成标准JSON数组以便后续遍历，期望输出格式如下：

[
{
"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null},
{
"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null},
{"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null
},
]

此前尝试的多种方案均错误地给每个单独的JSON对象都包裹了[]，得到多个单元素数组并列的错误结果，格式如下：

[{
"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null}],
[{
"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null}],
[{"title":"Hello this is a test",
"date":"05/04/2022",
"description":"this is a test",
"content":"<h1>Hello</h1>\n<h2>subhello</h2>",
"socials":null
}],

曾尝试使用回调方案解决但未成功，现寻求正确的实现方法。

内容的提问来源于stack exchange，提问作者Gianni Crivello