feat: Refine CJS/ESM build configuration for browser SDK. (#640)

The goals here are to:
- Make the build simpler.
- Make the build "modern".

Currently we have worked around some build issues in other packages.
Mainly with node module resolution. Despite the settings in the
package.json node wants certain file extensions for certain types
including .cts for the CJS type definitions.

So far tsup seems to be the simplest way to get all things with expected
names without a multi-step process. Or without having to make a hack
package.json that just has the modules type.

Please review #637 first.

packages/sdk/browser/contract-tests/entity/src/makeLogger.ts

@@ -2,19 +2,19 @@ import { LDLogger } from '@launchdarkly/js-client-sdk';
 
 export function makeLogger(tag: string): LDLogger {
   return {
-    debug(message, ...args: any[]) {
+    debug(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.debug(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
-    info(message, ...args: any[]) {
+    info(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.info(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
-    warn(message, ...args: any[]) {
+    warn(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.warn(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },
-    error(message, ...args: any[]) {
+    error(message: any, ...args: any[]) {
       // eslint-disable-next-line no-console
       console.error(`${new Date().toISOString()} [${tag}]: ${message}`, ...args);
     },

packages/sdk/browser/package.json

@@ -16,25 +16,38 @@
     "feature management",
     "sdk"
   ],
+  "type": "module",
+  "main": "./dist/index.cjs",
+  "module": "./dist/index.js",
+  "types": "./dist/index.d.ts",
   "exports": {
     ".": {
-      "types": "./dist/src/index.d.ts",
-      "require": "./dist/index.cjs.js",
-      "import": "./dist/index.es.js"
+      "require": {
+        "types": "./dist/index.d.cts",
+        "require": "./dist/index.cjs"
+      },
+      "import": {
+        "types": "./dist/index.d.ts",
+        "import": "./dist/index.js"
+      }
     },
     "./compat": {
-      "types": "./dist/src/compat/index.d.ts",
-      "require": "./dist/compat.cjs.js",
-      "import": "./dist/compat.es.js"
+      "require": {
+        "types": "./dist/compat.d.cts",
+        "require": "./dist/compat.cjs"
+      },
+      "import": {
+        "types": "./dist/compat.d.ts",
+        "import": "./dist/compat.js"
+      }
     }
   },
-  "type": "module",
   "files": [
     "dist"
   ],
   "scripts": {
     "clean": "rimraf dist",
-    "build": "tsc --noEmit && rollup -c rollup.config.js",
+    "build": "tsup",
     "lint": "eslint . --ext .ts,.tsx",
     "prettier": "prettier --write '**/*.@(js|ts|tsx|json|css)' --ignore-path ../../../.prettierignore",
     "test": "npx jest --runInBand",
@@ -46,11 +59,6 @@
   },
   "devDependencies": {
     "@jest/globals": "^29.7.0",
-    "@rollup/plugin-commonjs": "^25.0.0",
-    "@rollup/plugin-json": "^6.1.0",
-    "@rollup/plugin-node-resolve": "^15.0.2",
-    "@rollup/plugin-terser": "^0.4.3",
-    "@rollup/plugin-typescript": "^11.1.1",
     "@trivago/prettier-plugin-sort-imports": "^4.1.1",
     "@types/jest": "^29.5.11",
     "@typescript-eslint/eslint-plugin": "^6.20.0",
@@ -66,9 +74,8 @@
     "jest-environment-jsdom": "^29.7.0",
     "prettier": "^3.0.0",
     "rimraf": "^5.0.5",
-    "rollup": "^3.23.0",
-    "rollup-plugin-visualizer": "^5.12.0",
     "ts-jest": "^29.1.1",
+    "tsup": "^8.3.5",
     "typedoc": "0.25.0",
     "typescript": "^5.5.3"
   }

packages/sdk/browser/tsconfig.json

@@ -8,28 +8,27 @@
     "moduleResolution": "node",
     "noImplicitOverride": true,
     "resolveJsonModule": true,
-    // Uses "." so it can load package.json.
     "rootDir": ".",
     "outDir": "dist",
     "skipLibCheck": true,
-    // enables importers to jump to source
-    "sourceMap": true,
+    "sourceMap": false,
     "strict": true,
     "stripInternal": true,
     "target": "ES2017",
     "types": ["node", "jest"],
     "allowJs": true
   },
+  "include": ["src"],
   "exclude": [
     "vite.config.ts",
     "__tests__",
     "dist",
     "docs",
     "example",
     "node_modules",
-    "contract-tests",
     "babel.config.js",
-    "jestSetupFile.ts",
+    "setup-jest.js",
+    "rollup.config.js",
     "**/*.test.ts*"
   ]
 }

packages/sdk/browser/tsup.config.ts

@@ -0,0 +1,27 @@
+// It is a dev dependency and the linter doesn't understand.
+// eslint-disable-next-line import/no-extraneous-dependencies
+import { defineConfig } from 'tsup';
+
+export default defineConfig({
+  entry: {
+    index: 'src/index.ts',
+    compat: 'src/compat/index.ts',
+  },
+  minify: true,
+  format: ['esm', 'cjs'],
+  splitting: false,
+  sourcemap: false,
+  clean: true,
+  noExternal: ['@launchdarkly/js-sdk-common', '@launchdarkly/js-client-sdk-common'],
+  dts: true,
+  metafile: true,
+  esbuildOptions(opts) {
+    // This would normally be `^_(?!meta|_)`, but go doesn't support negative look-ahead assertions,
+    // so we need to craft something that works without it.
+    // So start of line followed by a character that isn't followed by m or underscore, but we
+    // want other things that do start with m, so we need to progressively handle more characters
+    // of meta with exclusions.
+    // eslint-disable-next-line no-param-reassign
+    opts.mangleProps = /^_([^m|_]|m[^e]|me[^t]|met[^a])/;
+  },
+});