调试器

🌐 Debugger

Node.js 包含一个命令行调试工具。Node.js 调试器客户端并不是一个功能齐全的调试器，但可以进行简单的逐步执行和检查。

🌐 Node.js includes a command-line debugging utility. The Node.js debugger client is not a full-featured debugger, but simple stepping and inspection are possible.

要使用它，请使用 inspect 参数启动 Node.js，然后跟上要调试的脚本路径。

🌐 To use it, start Node.js with the inspect argument followed by the path to the script to debug.

$ node inspect myscript.js
< Debugger listening on ws://127.0.0.1:9229/621111f9-ffcb-4e82-b718-48a145fa5db8
< For help, see: https://nodejs.cn/docs/inspector
<
connecting to 127.0.0.1:9229 ... ok
< Debugger attached.
<
 ok
Break on start in myscript.js:2
  1 // myscript.js
> 2 global.x = 5;
  3 setTimeout(() => {
  4   debugger;
debug> 拷贝

调试器会自动在第一个可执行行处中断。若希望运行到第一个断点（由 debugger 语句指定），请将环境变量 NODE_INSPECT_RESUME_ON_START 设置为 1。

🌐 The debugger automatically breaks on the first executable line. To instead run until the first breakpoint (specified by a debugger statement), set the NODE_INSPECT_RESUME_ON_START environment variable to 1.

$ cat myscript.js
// myscript.js
global.x = 5;
setTimeout(() => {
  debugger;
  console.log('world');
}, 1000);
console.log('hello');
$ NODE_INSPECT_RESUME_ON_START=1 node inspect myscript.js
< Debugger listening on ws://127.0.0.1:9229/f1ed133e-7876-495b-83ae-c32c6fc319c2
< For help, see: https://nodejs.cn/docs/inspector
<
connecting to 127.0.0.1:9229 ... ok
< Debugger attached.
<
< hello
<
break in myscript.js:4
  2 global.x = 5;
  3 setTimeout(() => {
> 4   debugger;
  5   console.log('world');
  6 }, 1000);
debug> next
break in myscript.js:5
  3 setTimeout(() => {
  4   debugger;
> 5   console.log('world');
  6 }, 1000);
  7 console.log('hello');
debug> repl
Press Ctrl+C to leave debug repl
> x
5
> 2 + 2
4
debug> next
< world
<
break in myscript.js:6
  4   debugger;
  5   console.log('world');
> 6 }, 1000);
  7 console.log('hello');
  8
debug> .exit
$ 拷贝

repl 命令允许远程评估代码。next 命令会执行到下一行。输入 help 查看其他可用命令。

🌐 The repl command allows code to be evaluated remotely. The next command steps to the next line. Type help to see what other commands are available.

在未输入命令而按下 enter 时，将会重复上一条调试命令。

🌐 Pressing enter without typing a command will repeat the previous debugger command.