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javascript - 为什么它在保存的文件中添加反斜杠？

问题描述

我有一些代码应该已经在 .json 文件中保存了一个单词和其他单词，它有点完成这项工作，它将文件（fs.readFileSync）作为常量读取，当使用 fs.WriteFileSync 保存时它只是随机放置' s 在这样的文本中在此处输入图像描述

我不知道它为什么这样做，但它真的很烦人（readBl 是一个读取它并将它保存为变量的函数，所以当我想要它时，我可以用命令让它读取它，我知道我可以做到以其他方式，但 IDC）我的代码：

if(msg.content.startsWith('-addconf '))
  {
    var newword = msg.content.slice(9);

    if(blacklisted.includes(newword))
      return msg.channel.sendMessage("This word has already been blacklisted.")

    let rawdata = fs.readFileSync('blacklist.json');
    let rawRead = JSON.parse(rawdata);

    const str = JSON.stringify(rawRead);

    const str1 = str.replace('}', '');
    const str2 = str1.replace('{"blacklist":', '');
    //const str3 = str2.replace('""', '');

    let balance = {
    blacklist: str2 + newword
    };

    let data = JSON.stringify(balance);
    fs.writeFileSync('blacklist.json', data);

    readBl();
    msg.channel.sendMessage("Added a blacklisted word, test it out.")
}

标签： javascriptjsondiscorddiscord.jsfs

解决方案

A JSON value (like the keys) is enclosed in double quotes.

{ "someKey": "someValue" }

So, how do you write a value that has quotes in it, like some"Value"With"Quotes"In"It? And you could have much much worse here...

(and more importantly, how does a JSON parser should read back such a value?

Is the value some? Is this a syntax error?

In JSON, like in many other contexts where you need to have delimiters, we need to have a way to tell that the quote " is not the syntax element to end the value, but some character that is part of the value.

The solution: escaping

So we do what is called "escaping" the character. In JSON (and in other languages), the escaping is done by prefixing with a backslash \.

And... since backslash is now a special character as well, that is used for escaping another character, you have the same problem again: how to represent a actual backslash in the value itself?

Simple, same solution: you escape the backslash itself.

So, when saving a JSON string value:

  • quotes " become \";
  • backslashes \ become \\.

How to read that back?

Any functioning JSON reader will read that properly, it's the correct way to serialize those characters, so you don't have any issue here!

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