Inspector
目录
Added in: v8.0.0
源代码: lib/inspector.js
The node:inspector
module provides an API for interacting with the V8
inspector.
It can be accessed using:
MJS
CJS
or
MJS
CJS
Promises API
Added in: v19.0.0
C inspector.Session
- Extends:
EventEmitter
The inspector.Session
is used for dispatching messages to the V8 inspector
back-end and receiving message responses and notifications.
M new inspector.Session()
Added in: v8.0.0
Create a new instance of the inspector.Session
class. The inspector session
needs to be connected through session.connect()
before the messages
can be dispatched to the inspector backend.
E 'inspectorNotification'
Added in: v8.0.0
Object
The notification message object
Emitted when any notification from the V8 Inspector is received.
JS
It is also possible to subscribe only to notifications with specific method:
E <inspector-protocol-method>
;
Added in: v8.0.0
Object
The notification message object
Emitted when an inspector notification is received that has its method field set
to the <inspector-protocol-method>
value.
The following snippet installs a listener on the 'Debugger.paused'
event, and prints the reason for program suspension whenever program
execution is suspended (through breakpoints, for example):
JS
M session.connect()
Added in: v8.0.0
Connects a session to the inspector back-end.
M session.connectToMainThread()
Added in: v12.11.0
Connects a session to the main thread inspector back-end. An exception will be thrown if this API was not called on a Worker thread.
M session.disconnect()
Added in: v8.0.0
Immediately close the session. All pending message callbacks will be called
with an error. session.connect()
will need to be called to be able to send
messages again. Reconnected session will lose all inspector state, such as
enabled agents or configured breakpoints.
M session.post(method[, params])
Added in: v19.0.0
Posts a message to the inspector back-end.
MJS
The latest version of the V8 inspector protocol is published on the Chrome DevTools Protocol Viewer.
Node.js inspector supports all the Chrome DevTools Protocol domains declared by V8. Chrome DevTools Protocol domain provides an interface for interacting with one of the runtime agents used to inspect the application state and listen to the run-time events.
Example usage
Apart from the debugger, various V8 Profilers are available through the DevTools protocol.
CPU profiler
Here's an example showing how to use the CPU Profiler:
MJS
Heap profiler
Here's an example showing how to use the Heap Profiler:
MJS
Callback API
C inspector.Session
- Extends:
EventEmitter
The inspector.Session
is used for dispatching messages to the V8 inspector
back-end and receiving message responses and notifications.
M new inspector.Session()
Added in: v8.0.0
Create a new instance of the inspector.Session
class. The inspector session
needs to be connected through session.connect()
before the messages
can be dispatched to the inspector backend.
E 'inspectorNotification'
Added in: v8.0.0
Object
The notification message object
Emitted when any notification from the V8 Inspector is received.
JS
It is also possible to subscribe only to notifications with specific method:
E <inspector-protocol-method>
;
Added in: v8.0.0
Object
The notification message object
Emitted when an inspector notification is received that has its method field set
to the <inspector-protocol-method>
value.
The following snippet installs a listener on the 'Debugger.paused'
event, and prints the reason for program suspension whenever program
execution is suspended (through breakpoints, for example):
JS
M session.connect()
Added in: v8.0.0
Connects a session to the inspector back-end.
M session.connectToMainThread()
Added in: v12.11.0
Connects a session to the main thread inspector back-end. An exception will be thrown if this API was not called on a Worker thread.
M session.disconnect()
Added in: v8.0.0
Immediately close the session. All pending message callbacks will be called
with an error. session.connect()
will need to be called to be able to send
messages again. Reconnected session will lose all inspector state, such as
enabled agents or configured breakpoints.
M session.post(method[, params][, callback])
历史
版本 | 更改 |
---|---|
v18.0.0 | Passing an invalid callback to the `callback` argument now throws `ERR_INVALID_ARG_TYPE` instead of `ERR_INVALID_CALLBACK`. |
v8.0.0 | Added in: v8.0.0 |
Posts a message to the inspector back-end. callback
will be notified when
a response is received. callback
is a function that accepts two optional
arguments: error and message-specific result.
JS
The latest version of the V8 inspector protocol is published on the Chrome DevTools Protocol Viewer.
Node.js inspector supports all the Chrome DevTools Protocol domains declared by V8. Chrome DevTools Protocol domain provides an interface for interacting with one of the runtime agents used to inspect the application state and listen to the run-time events.
Example usage
Apart from the debugger, various V8 Profilers are available through the DevTools protocol.
CPU profiler
Here's an example showing how to use the CPU Profiler:
JS
Heap profiler
Here's an example showing how to use the Heap Profiler:
JS
Common Objects
M inspector.close()
历史
版本 | 更改 |
---|---|
v18.10.0 | The API is exposed in the worker threads. |
v9.0.0 | Added in: v9.0.0 |
Deactivate the inspector. Blocks until there are no active connections.
M inspector.console
Object
An object to send messages to the remote inspector console.
JS
The inspector console does not have API parity with Node.js console.
M inspector.open([port[, host[, wait]]])
port
number
Port to listen on for inspector connections. Optional. Default: what was specified on the CLI.host
string
Host to listen on for inspector connections. Optional. Default: what was specified on the CLI.wait
boolean
Block until a client has connected. Optional. Default:false
.
Activate inspector on host and port. Equivalent to
node --inspect=[[host:]port]
, but can be done programmatically after node has
started.
If wait is true
, will block until a client has connected to the inspect port
and flow control has been passed to the debugger client.
See the security warning regarding the host
parameter usage.
M inspector.url()
Return the URL of the active inspector, or undefined
if there is none.
BASH
M inspector.waitForDebugger()
Added in: v12.7.0
Blocks until a client (existing or connected later) has sent
Runtime.runIfWaitingForDebugger
command.
An exception will be thrown if there is no active inspector.