fix(compat/function/debounce): skip maxWait invocation when both leading and trailing are false

[sukvvon]

Summary

• Guard maxWait forced invocation with leading || trailing check in compat debounce
• When both leading and trailing are false, maxWait expiry no longer triggers function execution, matching lodash behavior
• Add regression tests for both compat debounce and compat throttle

Root Cause

The compat debounce unconditionally called func.apply() when maxWait elapsed, ignoring the leading/trailing options. Lodash skips execution when both edges are disabled — even if maxWait is reached.

This was previously attempted in #1560 (workaround in throttle), which was reverted. This fix addresses the root cause in debounce itself, as suggested by @raon0211.

Fixes #1494

Test Plan

• Added test: compat debounce with { leading: false, trailing: false, maxWait: 64 } → 0 invocations
• Added test: compat throttle with { leading: false, trailing: false } → 0 invocations
• All existing 4333 tests pass
• Verified output matches lodash for all 4 leading/trailing combinations

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Project	Deployment	Actions	Updated (UTC)
es-toolkit	Ready	Preview, Comment	Apr 3, 2026 11:20am