function debuglog
Usage in Deno
```typescript import { debuglog } from "node:node__util.d.ts"; ```
debuglog(section: string,callback?: (fn: DebugLoggerFunction) => void,): DebugLogger
The `util.debuglog()` method is used to create a function that conditionally
writes debug messages to `stderr` based on the existence of the `NODE_DEBUG`environment variable. If the `section` name appears within the value of that
environment variable, then the returned function operates similar to `console.error()`. If not, then the returned function is a no-op.
```js
import util from 'node:util';
const debuglog = util.debuglog('foo');
debuglog('hello from foo [%d]', 123);
```
If this program is run with `NODE_DEBUG=foo` in the environment, then
it will output something like:
```console
FOO 3245: hello from foo [123]
```
where `3245` is the process id. If it is not run with that
environment variable set, then it will not print anything.
The `section` supports wildcard also:
```js
import util from 'node:util';
const debuglog = util.debuglog('foo-bar');
debuglog('hi there, it\'s foo-bar [%d]', 2333);
```
if it is run with `NODE_DEBUG=foo*` in the environment, then it will output
something like:
```console
FOO-BAR 3257: hi there, it's foo-bar [2333]
```
Multiple comma-separated `section` names may be specified in the `NODE_DEBUG`environment variable: `NODE_DEBUG=fs,net,tls`.
The optional `callback` argument can be used to replace the logging function
with a different function that doesn't have any initialization or
unnecessary wrapping.
```js
import util from 'node:util';
let debuglog = util.debuglog('internals', (debug) => {
// Replace with a logging function that optimizes out
// testing if the section is enabled
debuglog = debug;
});
```
A string identifying the portion of the application for which the `debuglog` function is being created.
optional
callback: (fn: DebugLoggerFunction) => void
A callback invoked the first time the logging function is called with a function argument that is a more optimized logging function.
The logging function