Bug: [BUG] Child instance cannot import settings from parent

[dever23b]

Describe the bug
The LoggerWithoutCallSite.settings getter method merges this._parentOrDefaultSettings and this._mySettings in a manner which results . As of this writing, the code uses spread operators to merge the two property sets; however, this method of merging simply overwrites and does not prevent a "falsy" value from overwriting a "truthy" value. Accordingly, settings that are left undefined in a child will still overwrite the corresponding setting from the parent. The merging process must consider whether a child setting is defined prior to overwriting the defaults, or the defaults will never be used.

To Reproduce
Steps to reproduce the behavior:

import { Logger } from 'tslog';
const parent = new Logger({ name: 'parent' }); // parent.settings.name = 'parent'
const child = parent.getChildLogger({ requestId: 'foo' }); // parent.settings.name = undefined

child.info('test'); 
// when eventually passed through prettyPrintLog, 
// parent.settings.name is evaluated to undefined and not printed

Expected behavior
Child logger settings should be merged with parent, as the documentation suggests, such that only defined settings overwrite parent/defaults.

Additional context

tslog/src/LoggerWithoutCallSite.ts

Lines 133 to 141 in bbc8bab

	public get settings(): ISettings {
	const myPrefix: unknown[] =
	this._mySettings.prefix != null ? this._mySettings.prefix : [];
	return {
	...this._parentOrDefaultSettings,
	...this._mySettings,
	prefix: [...this._parentOrDefaultSettings.prefix, ...myPrefix],
	};
	}

Node.js Version
v16.16.0

[terehov]

@dever23b Thank you for reporting this bug.

However, the faulty code isn't the spread operator, it's rather here:

tslog/src/LoggerWithoutCallSite.ts

Lines 170 to 176 in bbc8bab

	this._mySettings.name =
	this._mySettings.name ??
	(this._mySettings.setCallerAsLoggerName
	? LoggerHelper.getCallSites()?.[0]?.getTypeName() ??
	LoggerHelper.getCallSites()?.[0]?.getFunctionName() ??
	undefined
	: undefined);

It's the way the name gets replaced in certain scenarios. I have fixed it and going to publish a new version with some more bugfixes shortly.

[terehov]

https://github.com/fullstack-build/tslog/releases/tag/v3.3.4

[dever23b]

Thanks! I'll get updated and test this week.

[dever23b]

I pulled the latest version and tested this. It works! Thanks again.