NodeJS Bug？执行返回字符串之前带换行符的return语句时出错[重复]

时间：2022-01-09 10:28:25

This question already has an answer here:

这个问题在这里已有答案：

I'm trying call a function, from a module, to build a HTML string. When the function is written in the below way, with a LF(Line Feed) between the return statement and the string declaration, the return is "undefined"...

我正在尝试从模块调用函数来构建HTML字符串。当函数以下面的方式写入时，在return语句和字符串声明之间使用LF（换行符），返回是“未定义的”...

exports.buildHtmlContent = function (content) {
    return
    "<!DOCTYPE html>                    \
    \n<html lang='en-US'>               \
    \n  <head>                          \
    \n  </head>                         \
    \n  <body>                          \
    \n      <h1>" + content + "</h1>    \
    \n  </body>                         \
    \n</html>";
};

However, when the function is written in this other below way, without the LF after return statement, it works properly!

但是，当函数以下面的方式写入，在返回语句后没有LF，它可以正常工作！

exports.buildHtmlContent = function (content) {
    return "<!DOCTYPE html>             \
    \n<html lang='en-US'>               \
    \n  <head>                          \
    \n  </head>                         \
    \n  <body>                          \
    \n      <h1>" + content + "</h1>    \
    \n  </body>                         \
    \n</html>";
};

This is a bug in NodeJs? The NodeJs interpretation from the function 1 looks like it thinks the return is empty, even with the miss of ";", and didn't correlate the below string declaration with the return statement. Apparently NodeJs didn't check the miss of ";" before decide that is the interpretation end of the "return" statement.

这是NodeJs中的一个错误？函数1中的NodeJs解释看起来像是认为返回为空，即使缺少“;”，并且没有将下面的字符串声明与return语句相关联。显然NodeJ没有检查错过“;”在决定是“返回”声明的解释结束之前。

1 个解决方案

#1

3  

This has to do with JavaScript, and not Node.js specifically. Most JavaScript engines implement Automatic Semi-colon Insertion, meaning that it will try to automatically separate two clauses with a semi-colon. The statement return on its own is valid, as it will return undefined, and a string is a valid statement as well. For example:

这与JavaScript有关，而不是与Node.js有关。大多数JavaScript引擎实现自动半冒号插入，这意味着它将尝试使用分号自动分隔两个子句。语句返回本身是有效的，因为它将返回undefined，并且字符串也是有效的语句。例如：

"use strict";

The reason why ASI is triggered is due to both the line break, and return being a restricted production. Not a bug, but a feature.

触发ASI的原因是由于换行和返回都是限制生产。不是错误，而是一个功能。

#1

3  

This has to do with JavaScript, and not Node.js specifically. Most JavaScript engines implement Automatic Semi-colon Insertion, meaning that it will try to automatically separate two clauses with a semi-colon. The statement return on its own is valid, as it will return undefined, and a string is a valid statement as well. For example:

这与JavaScript有关，而不是与Node.js有关。大多数JavaScript引擎实现自动半冒号插入，这意味着它将尝试使用分号自动分隔两个子句。语句返回本身是有效的，因为它将返回undefined，并且字符串也是有效的语句。例如：

"use strict";

The reason why ASI is triggered is due to both the line break, and return being a restricted production. Not a bug, but a feature.

触发ASI的原因是由于换行和返回都是限制生产。不是错误，而是一个功能。

标签：

相关文章