CON-2075: replace merge-deep with deepmerge#145
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Drops the unmaintained merge-deep dependency (along with 15 transitive CommonJS micro-packages) in favor of deepmerge — a zero-dependency, ESM-friendly library with built-in TypeScript types. A custom arrayMerge option preserves the ordered-unique-concat (union) semantics that merge-deep exposed via arr-union, so callers that rely on the old array handling see no behavior change. New characterization tests in test/base-api-merge.spec.ts pin the deep-merge contract (library-level + SmartlingBaseApi integration) and all 234 tests pass on both the old and new dependency. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…verage Move the deep-merge helper out of base-api.ts into api/base/merge.ts so it no longer looks like a public symbol on the main API surface. Tighten its signature from any to a generic T & U to drop the eslint-disable. Strip ticket-id and migration framing from comments so they stay useful after the merge-deep swap is ancient history. Extend test coverage with null/undefined source values, array vs object type mismatches, reference-based array-of-objects dedup, two prototype pollution cases, and an integration test that flows array-valued headers through setOptions to prove the arrayMerge option is reached in production. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…erge Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
PavelLoparev
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dnetrebenko-smartling and
vsolovei-smartling
dimitrystd
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Apr 17, 2026
vsolovei-smartling
approved these changes
Apr 18, 2026
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Summary
merge-deep@3.0.3fordeepmerge@^4.3.1(CON-2075, #144)package-lock.json(merge-deep,arr-union,clone-deep,kind-of+ deps); adds ~4 KB, zero-dep, ESM-friendlydeepmergewith built-in TS typesarrayMergeoption so existing callers see zero behavior changetest/base-api-merge.spec.tswith 19 characterization tests (13 library-level + 6SmartlingBaseApiintegration) that pin the deep-merge contract across the swapWhy array semantics matter
merge-deepdelegates array handling toarr-union, which de-duplicates while preserving order ([1,2,3] + [2,3,4] → [1,2,3,4]).deepmerge's default is plain concat ([1,2,3,2,3,4]). The customarrayMergeinmergeOptionsreproduces the old union behavior exactly, so any caller that passed header/option arrays and relied on dedup stays correct.Test plan
merge-deep(before swap)deepmerge(after swap) — proves paritynpm test(lint + build + coverage) — 234 passing, 0 failuresnpm run pretest— no new lint errors (3 pre-existing warnings onsensitiveReplacerunchanged)🤖 Generated with Claude Code