feat(errors): bind constructCb's this to the new instance via fnCall

[nev21]

constructCb is now invoked with fnCall(constructCb, _self, _self, theArgs, isOwnInstance) instead of a plain call, so this inside the callback refers to the new error instance in addition to receiving it as the first argument. Lets constructCb implementations use this.prop = ... instead of requiring the first (self) argument.

Also pass the resolved leaf constructor (_ctor) directly to captureStackTrace instead of re-reading it off _this[CONSTRUCTOR], avoiding a redundant lookup since isOwnInstance already guarantees they're equal.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.17%. Comparing base (efca6c5) to head (5a60db2).

Additional details and impacted files

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##             main     #589   +/-   ##
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  Coverage   99.17%   99.17%           
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  Files         179      179           
  Lines        5479     5481    +2     
  Branches     1210     1214    +4     
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+ Hits         5434     5436    +2     
  Misses         45       45           

Files with missing lines	Coverage Δ
lib/src/helpers/customError.ts	100.00% <100.00%> (ø)

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[Copilot]

Pull request overview

This PR updates createCustomError()’s construction path so that constructCb is invoked with this bound to the newly created error instance (in addition to receiving it as the first argument), and slightly streamlines stack capture by reusing the resolved leaf constructor.

Changes:

• Bind constructCb’s this to the error instance via fnCall(...) while preserving existing callback arguments.
• Avoid a redundant constructor lookup when calling Error.captureStackTrace by passing _ctor directly.
• Minor control-flow refactor around stack capture / callback invocation.

[nevware21-bot]

Approved by nevware21-bot

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

lib/src/helpers/customError.ts:60

• The JSDoc currently implies the constructCb this binding behavior is “(Since v0.16.0)”, but that version tag previously applied to the isOwnInstance argument (and this binding is being introduced here). Also, referencing argument positions becomes confusing once a this parameter is added to the TypeScript type. Consider rewording to describe the actual runtime signature (self, args, isOwnInstance) and separately state that this is bound to self.

 * new Custom Error instance is being created. (Since v0.16.0) The callback is invoked with `this` bound to
 * the same instance that is also passed as the `self` (1st) argument, so implementations may use either
 * `this.prop = ...` or `self.prop = ...` interchangeably - this only applies when `constructCb` is a normal
 * (non-arrow) function, as arrow functions ignore the bound `this` and keep their own lexically captured value.
 * The 3rd argument, `isOwnInstance`, is `true` when this class is the leaf-most (most-derived) type actually

[nevware21-bot]

Approved by nevware21-bot