Update ts-jest config (#533)

Author: drwpow

jest.config.js

@@ -1,4 +1,9 @@
 module.exports = {
   preset: "ts-jest",
   testEnvironment: "node",
+  globals: {
+    "ts-jest": {
+      tsconfig: "tsconfig.jest.json",
+    },
+  },
 };

tsconfig.jest.json

@@ -0,0 +1,21 @@
+{
+  "compilerOptions": {
+    "baseUrl": "./src",
+    "declaration": true,
+    "esModuleInterop": true,
+    "lib": ["ESNext"],
+    "module": "ESNext",
+    "moduleResolution": "node",
+    "noImplicitAny": true,
+    "noImplicitReturns": true,
+    "noUnusedLocals": true,
+    "outDir": "./dist/esm",
+    "removeComments": true,
+    "skipLibCheck": true,
+    "sourceMap": true,
+    "strict": true,
+    "target": "ES2018"
+  },
+  "include": ["src"],
+  "exclude": ["examples/*", "tests/**/*"]
+}