fix: cjs + esm + umd module

package.json

@@ -2,10 +2,16 @@
   "name": "@govtechsg/oa-schemata",
   "version": "0.0.0-development",
   "description": "Repository for schemata created by open-attestation",
+  "main": "dist/cjs/index.js",
+  "module": "dist/esm/index.js",
+  "browser": "dist/index.umd.js",
   "types": "dist/types/index.d.ts",
   "scripts": {
-    "build": "npm run clean && npm run build:type",
+    "build": "npm run clean && npm run build:cjs && npm run build:esm && npm run build:umd && npm run build:type",
+    "build:cjs": "tsc --module commonjs --outDir dist/cjs --project ./tsconfig.prod.json",
+    "build:esm": "tsc --module es2015 --outDir dist/esm --project ./tsconfig.prod.json",
     "build:type": "tsc -d --emitDeclarationOnly --outDir dist/types",
+    "build:umd": "rollup -c",
     "clean": "rm -rf dist/",
     "dev": "cd app && npm run dev",
     "test": "jest",
@@ -21,6 +27,7 @@
     "@commitlint/config-conventional": "8.3.3",
     "@commitlint/prompt": "8.3.3",
     "@ls-age/commitlint-circle": "1.0.0",
+    "@rollup/plugin-json": "^4.0.0",
     "@types/jest": "^24.0.23",
     "@types/lodash": "^4.14.162",
     "@typescript-eslint/eslint-plugin": "^2.8.0",
@@ -41,6 +48,8 @@
     "prettier": "^1.19.1",
     "prettier-plugin-svelte": "^1.4.1",
     "quicktype": "^15.0.258",
+    "rollup": "^1.27.3",
+    "rollup-plugin-commonjs": "^10.1.0",
     "semantic-release": "^17.2.1",
     "svelte": "^3.29.4",
     "ts-jest": "^24.1.0",

rollup.config.js

@@ -0,0 +1,12 @@
+import commonjs from "rollup-plugin-commonjs";
+import json from "@rollup/plugin-json";
+
+export default {
+  input: "./dist/esm/index.js", // umd will run from esm build to produce a single bundled file, any better idea ?
+  output: {
+    file: "./dist/index.umd.js",
+    format: "umd",
+    name: "openAttestation"
+  },
+  plugins: [commonjs(), json()]
+};

tsconfig.prod.json

@@ -0,0 +1,6 @@
+{
+  "extends": "./tsconfig",
+  "exclude": [
+    "**/*.test.ts"
+  ]
+}