… API

Adds lib/utils/bytes.js helper (hexToBytes/bytesToHex/base64ToBytes/bytesToBase64/concatBytes/bytesEqual) and converts all Buffer.* call sites in dapi-client lib/ to Uint8Array, with corresponding test updates. Package stays CJS.

Production exceptions where Buffer is retained: BlockHeadersReader passes Buffer to dashcore-lib's BlockHeader (its BufferReader needs .readInt32LE), and GetIdentitiesContractKeysResponse passes Buffer to wasm-dpp's Identifier.from (it explicitly requires Node Buffer).

createGrpcTransportError now handles both raw bytes (grpc-js path) and base64 strings (grpc-web path) for drive-error-data-bin, stack-bin, and dash-serialized-consensus-error-bin metadata fields, restoring the dual-format behavior that Buffer.from(x, 'base64') used to provide implicitly.

Test updates: spec files that construct expected protobuf requests now wrap .toBuffer() with new Uint8Array(...) to match production's normalization (sinon calledOnceWithExactly distinguishes Buffer from plain Uint8Array).

Breaking change for direct consumers: response object byte fields are now Uint8Array. Callers that do response.field.toString('hex') will fail — use bytesToHex(response.field) from lib/utils/bytes instead. Buffer.isBuffer(response.field) now returns false; use response.field instanceof Uint8Array.

Test results: dapi-client 315/315, wallet-lib 377/377, js-dash-sdk 60/60 — downstream consumers continue passing without modification (they exercise dapi-client mostly via mocks).

Converts @dashevo/dapi-client to pure ESM: type: module, exports map with ./lib/* wildcard, all CJS require/module.exports replaced with import/export, .js extensions on relative imports. Engine bumped to >=18.18.

Drops webpack.config.js, karma.conf.js, and lib/test/karma/. Removes the @babel/core, babel-loader, browser-polyfill, karma, and webpack devDeps. Consumers must use a modern bundler (Vite/esbuild/webpack 5) which handles ESM natively.

Moves 'events' npm package from devDependencies to dependencies — used by DAPIClient, ReconnectableStream, and BlockHeadersProvider for EventEmitter, and resolves correctly in both Node and browser bundlers.

BREAKING: CJS consumers (require) no longer work. Downstream consumers wallet-lib (PR 4) and js-dash-sdk (PR 5) are temporarily broken between this PR merging and PRs 4/5 merging — they must land as a sequence. Dashmate is already ESM and continues to work.

Test results: dapi-client 315/315. wallet-lib + js-dash-sdk fail as expected (fixed by PRs 4 + 5).

Converts @dashevo/wallet-lib to pure ESM so it can consume the ESM dapi-client from PR 3. Adds 'type: module' to package.json. All src/, fixtures/, and tests/ files converted from CJS require/module.exports to ESM import/export with .js extensions on relative imports.

Deletes webpack.config.js, karma/, src/test/karma/. Removes browser-polyfill devDeps (buffer, crypto-browserify, stream-browserify, etc.) and webpack/karma. Tests run via Mocha in Node 18+; browser builds are out of scope. Engines: >=18.18.

CJS-named-import fixes: lodash, crypto-js, @dashevo/dashcore-lib, @dashevo/wasm-dpp, @dashevo/grpc-common all use default-import + destructure pattern because Node ESM cannot statically enumerate named exports of CJS modules.

Surfaces three previously-silent CJS bugs that ESM strict mode catches: missing UnknownStrategy export from errors/index.js, missing named exports for coinSelection strategies, and a 'type=' implicit-global in DerivableKeyChain.spec.js.

Defensive (loadDpp.default ?? loadDpp)() unwrap in IdentitySyncWorker.onStart for the same wasm-dpp NodeNext interop reason as PR 3's bootstrap.

Test results: wallet-lib 377/377 passing. dapi-client unchanged (315/315). js-dash-sdk still broken (PR 5 fixes).

…SM dapi-client and wallet-lib

Final PR in the ESM migration stack. Converts the two remaining workspace packages that consumed dapi-client/wallet-lib, restoring monorepo-wide green tests after PR 3.

js-dash-sdk: TypeScript-based package with NodeNext module resolution. Adds 'type: module' + exports map. tsconfig.build.json → module: nodenext, moduleResolution: nodenext, target: es2020. All .ts files get .js extensions on relative imports (TS NodeNext compiles .ts to .js but the import string must already say .js). Drops ts-mock-imports by refactoring register.ts to accept an injectable randomBytes parameter (ts-mock-imports relies on mutable module exports which ESM forbids). Deletes webpack/karma + browser polyfills. Replaces winston with console-backed logger. CJS-named-import conversions for @dashevo/dashcore-lib, @dashevo/wasm-dpp, @dashevo/grpc-common, and the system-id imports from contract packages. Adds parallel 'import type' aliases (via 'import type { X as XType }; type X = XType;') in 22 .ts files where destructured value names are also used as types — works around TS2440 namespace collision under NodeNext.

platform-test-suite: converted ~35 files from CJS to ESM. Test bootstrap converted; .mocharc.yml uses 'import:' for ESM root hooks.

Defensive (loadDpp.default ?? loadDpp)() unwrap in 4 sites (Platform.initializeDppModule, createIdentityFixtureInAccount, contracts/get.spec.ts, contracts/history.spec.ts). createGrpcTransportError-style dual-format byte handling preserved.

Test results: 752 passing across the monorepo (dapi-client 315, wallet-lib 377, js-dash-sdk 60). platform-test-suite is end-to-end and requires live testnet credentials in .env (pre-existing constraint).