Plan TypeScript 7 migration and modernize emitted JavaScript target

[TheRealAgentK]

Context

Raygun4Node currently builds with TypeScript 6.0.x, emits ES5 CommonJS, and declares Node.js >=14.17.0. Dependabot PR #530 attempted to update TypeScript from 6.0.3 to 7.0.2, but that cannot be treated as a dependency-only upgrade:

• TypeScript 7 removes target: "es5"; TypeScript 6 only preserves it behind ignoreDeprecations: "6.0".
• The current typescript-eslint toolchain supports TypeScript >=4.8.4 <6.1.0, so the automated PR fails during npm ci.
• TypeScript 7 is a native compiler with different configuration defaults and hard removals for options deprecated in TypeScript 6.
• The SDK is published as CommonJS and is consumed by the AWS Lambda provider. Module-format compatibility must not change accidentally as part of a compiler update.

PR #530 was intentionally closed and TypeScript 7 Dependabot updates were ignored for the current compatibility line. This issue is the durable record for adopting TypeScript 7 deliberately.

Official migration context:

• TypeScript 6 deprecates ES5 output and recommends a newer target or an external downlevel compiler.
• TypeScript 7 turns that deprecation into a hard error and uses ES2015 as its minimum output target.

Decisions required before implementation

1. Minimum supported Node.js version

   • Confirm whether >=14.17.0 remains a real customer requirement.
   • Review Node.js end-of-life status, actual SDK usage, and the CI support matrix.
   • Treat raising the runtime floor as an explicit compatibility/release decision, not a compiler side effect.

2. Emitted JavaScript target

   • Select and document a target supported by every retained Node.js runtime (at least ES2015; potentially ES2019/ES2020 depending on policy).
   • Decide whether TypeScript should emit the final target directly or whether an external downlevel compiler is required.

3. Module format

   • Preserve CommonJS unless a separately scoped package-format migration is approved.
   • Do not combine an ESM-only transition with the compiler upgrade by default.

4. Toolchain readiness

   • Use versions of typescript-eslint, ESLint integrations, ts-node, and test tooling that officially support TypeScript 7.
   • Do not bypass peer dependency checks with --force or --legacy-peer-deps.

5. Configuration defaults

   • Audit explicit target, module, moduleResolution, rootDir, types, lib, declaration, and interoperability settings against TypeScript 7 defaults.
   • Remove ignoreDeprecations only after all deprecated behavior has been replaced.

Proposed implementation sequence

1. Document/approve the Node.js runtime support policy and chosen JavaScript target.
2. Upgrade the TypeScript-adjacent lint/test toolchain to releases with official TS 7 support while still on TS 6 where possible.
3. Add a fixture or retained artifact comparison for the public JS/declaration package surface.
4. Change the output target as its own reviewable compatibility change and validate it across every supported Node version.
5. Upgrade TypeScript to 7 and address only compiler/configuration differences in that change.
6. Validate the AWS Lambda provider against a packed build of this package before release.

Acceptance criteria

• Minimum Node.js version and JavaScript output target are explicitly documented and approved.
• Release impact (major/minor and migration note requirements) is decided before merge.
• All TypeScript-related tools officially support the selected TS 7 version; installation succeeds without peer overrides.
• tsconfig.json contains explicit settings needed to prevent default-driven output/layout changes.
• CommonJS require("raygun") works on every supported Node.js version.
• Full unit, Express, batch, offline, uncaught exception, and CommonJS compatibility tests pass.
• npm pack contains the expected build/ JS and declaration entry points.
• Emitted declarations are reviewed for consumer-facing changes.
• A representative CommonJS consumer smoke test passes against the packed tarball.
• The AWS Lambda provider builds and passes its tests against the packed candidate.
• Changelog and migration guidance describe any runtime-floor or emitted-syntax change.

Non-goals

• Migrating the package to ESM unless separately approved.
• Changing runtime behavior unrelated to compiler output.
• Reopening Dependabot PR chore(deps-dev): bump typescript from 6.0.3 to 7.0.2 #530 without satisfying the policy and toolchain prerequisites above.

[TheRealAgentK]

Companion provider migration tracking: MindscapeHQ/raygun4node-aws-lambda#186. The Lambda migration should follow the runtime/output-target decision made here and validate against a packed core SDK candidate.