feat: introduce tsup for bundling (#25)

* chore: introduce tsup for bundling

Added the package `tsup` to assist in bundling `@mswjs/source`-package so
it both supports CommonJS and ESM modules. The `package.json` file has
been modified so the appropriate properties for the modern `exports`-approach
of exporting, and the older `main`-`module` combination.

During building and running the tests the `fromOpenApi` had issues
to pass the tests or build due to the way the `SwaggerParser` utility
class was exporter. The code has been updated so it refers to
the `deferences`-function via `SwaggerParser.deferences()` instead of trying
to instantiate the class.

For this reason the `tsconfig.json` has been updated so that it enables
`esModuleInterop` and `allowSyntheticDefaultImports` after this change
the package build and bundled successfully with `tsup` and passed the
unit tests, before errors like below were shown:

    src/fromOpenApi/fromOpenApi.ts:16:35 - error TS2351: This expression is not constructable.
      Type 'typeof SwaggerParser' has no construct signatures.

    16   const specification = await new SwaggerParser().dereference(document)
                                         ~~~~~~~~~~~~~

* chore: remove unused scripts

* chore: use "tsup" for local development

Co-authored-by: Weyert de Boer <weyert@innerfuse.biz>
Co-authored-by: Artem Zakharchenko <kettanaito@gmail.com>

package.json

@@ -2,19 +2,26 @@
   "name": "@mswjs/source",
   "version": "0.0.0",
   "description": "Generate request handlers for Mock Service Worker from various sources.",
-  "main": "lib/index.js",
-  "types": "lib/index.d.ts",
+  "main": "./lib/index.js",
+  "module": "./lib/index.mjs",
+  "types": "./lib/index.d.ts",
+  "exports": {
+    ".": {
+      "require": "./lib/index.cjs",
+      "import": "./lib/index.mjs"
+    }
+  },
   "repository": "git@github.com:mswjs/source.git",
   "author": "Artem Zakharchenko <kettanaito@gmail.com>",
   "license": "MIT",
   "scripts": {
-    "start": "tsc -w",
+    "start": "yarn build --watch",
     "lint": "eslint ./{src,test}/**/*.ts",
     "har:fixture": "ts-node test/traffic/fixtures/requests/command.ts",
-    "clean": "rimraf ./lib",
-    "build": "yarn lint && yarn clean && tsc",
+    "prebuild": "yarn lint",
+    "build": "tsup src/index.ts --format cjs,esm --out-dir lib --dts --clean",
     "test": "jest",
-    "prepublishOnly": "yarn build && yarn test:lib && yarn test"
+    "prepublishOnly": "yarn test && yarn build"
   },
   "files": [
     "lib",
@@ -59,6 +66,7 @@
     "ts-jest": "26.5.6",
     "ts-node": "^10.2.0",
     "tslib": "^2.3.1",
+    "tsup": "^5.11.13",
     "typescript": "^4.3.5"
   },
   "dependencies": {

src/fromOpenApi/fromOpenApi.ts

@@ -1,20 +1,18 @@
 import { RequestHandler, rest } from 'msw'
 import { OpenAPIV3, OpenAPIV2 } from 'openapi-types'
-import * as SwaggerParser from '@apidevtools/swagger-parser'
+import SwaggerParser from '@apidevtools/swagger-parser'
 import { createResponseResolver } from './response/createResponseResolver'
 import { normalizeSwaggerUrl } from './utils/normalizeSwaggerUrl'
 import { getServers } from './utils/getServers'
 import { joinPaths } from './utils/url'
 
-const parser = new SwaggerParser()
-
 /**
  * Generates request handlers from the given OpenAPI V2/V3 document.
  */
 export async function fromOpenApi(
   document: string | OpenAPIV3.Document | OpenAPIV2.Document,
 ): Promise<RequestHandler[]> {
-  const specification = await parser.dereference(document)
+  const specification = await SwaggerParser.dereference(document)
 
   const handlers = Object.entries(specification.paths).reduce<RequestHandler[]>(
     (

tsconfig.json

@@ -5,8 +5,9 @@
     "strict": true,
     "allowJs": false,
     "moduleResolution": "node",
+    "esModuleInterop": true,
     "downlevelIteration": true,
-    "allowSyntheticDefaultImports": false,
+    "allowSyntheticDefaultImports": true,
     "forceConsistentCasingInFileNames": true,
     "resolveJsonModule": true,
     "noImplicitAny": true,