debugger 调试器
Node.js 包含了一个命令行的调试实用工具。
要使用它,则使用 inspect
参数启动 Node.js,后跟要调试的脚本的路径。
$ node inspect myscript.js
< Debugger listening on ws://127.0.0.1:9229/621111f9-ffcb-4e82-b718-48a145fa5db8
< For help, see: https://nodejs.org/en/docs/inspector
<
< Debugger attached.
<
ok
Break on start in myscript.js:2
1 // myscript.js
> 2 global.x = 5;
3 setTimeout(() => {
4 debugger;
debug>
Node.js 调试器客户端不是功能齐全的调试器,但可以进行简单的步骤和检查。
将语句 debugger;
插入脚本的源代码,则将在代码中的该位置启用断点:
// myscript.js
global.x = 5;
setTimeout(() => {
debugger;
console.log('world');
}, 1000);
console.log('hello');
一旦调试器运行,则断点将出现在第 3 行:
$ node inspect myscript.js
< Debugger listening on ws://127.0.0.1:9229/621111f9-ffcb-4e82-b718-48a145fa5db8
< For help, see: https://nodejs.org/en/docs/inspector
<
< Debugger attached.
<
ok
Break on start in myscript.js:2
1 // myscript.js
> 2 global.x = 5;
3 setTimeout(() => {
4 debugger;
debug> cont
< 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
$
repl
命令允许远程评估代码。
next
命令步进下一行。
键入 help
以查看可用的其他命令。
在不输入命令的情况下按 enter
将重复之前的调试器命令。
Node.js includes a command-line debugging utility. 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.org/en/docs/inspector
<
< Debugger attached.
<
ok
Break on start in myscript.js:2
1 // myscript.js
> 2 global.x = 5;
3 setTimeout(() => {
4 debugger;
debug>
The Node.js debugger client is not a full-featured debugger, but simple step and inspection are possible.
Inserting the statement debugger;
into the source code of a script will
enable a breakpoint at that position in the code:
// myscript.js
global.x = 5;
setTimeout(() => {
debugger;
console.log('world');
}, 1000);
console.log('hello');
Once the debugger is run, a breakpoint will occur at line 3:
$ node inspect myscript.js
< Debugger listening on ws://127.0.0.1:9229/621111f9-ffcb-4e82-b718-48a145fa5db8
< For help, see: https://nodejs.org/en/docs/inspector
<
< Debugger attached.
<
ok
Break on start in myscript.js:2
1 // myscript.js
> 2 global.x = 5;
3 setTimeout(() => {
4 debugger;
debug> cont
< 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
$
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.
Pressing enter
without typing a command will repeat the previous debugger
command.