feat: add Terser config

Author: aminya

src/.terserrc.js

@@ -0,0 +1,40 @@
+const isDev = process.env.NODE_ENV === "development"
+const isTest = process.env.NODE_ENV === "test"
+const isReadable = isDev || isTest
+
+const ProductionCompress = {
+  global_defs: {
+    // remove dev and test specific code for production
+    "@atom.inSpecMode": !isTest ? "() => false" : "() => true",
+    "@atom.inDevMode": !isDev ? "() => false" : "() => true",
+  },
+  ecma: "2018",
+  toplevel: true,
+  hoist_vars: false,
+  hoist_funs: true,
+  pure_getters: true,
+  unsafe: true,
+  unsafe_arrows: true,
+  unsafe_comps: true,
+  unsafe_Function: true,
+  unsafe_math: true,
+  unsafe_symbols: true,
+  unsafe_methods: true,
+  unsafe_proto: true,
+  unsafe_regexp: true,
+  unsafe_undefined: true,
+  passes: 3,
+}
+
+const TerserOptions = {
+  // "module": false, // controlled by Parcel
+  compress: isDev ? false : ProductionCompress,
+  parse: {
+    ecma: 2020,
+  },
+  mangle: isReadable ? false : true,
+  format: {
+    beautify: isReadable,
+  },
+}
+module.exports = TerserOptions