refactor: ♻️ convert package to typescript

.eslintrc.js

@@ -44,7 +44,8 @@ module.exports = {
   parser: '@typescript-eslint/parser',
   parserOptions: {
     jsx: true,
-    ecmaVersion: 2018
+    ecmaVersion: 2018,
+    sourceType: "module"
   },
   overrides: [
     // linting for js files

.rollup/index.mjs

@@ -0,0 +1,52 @@
+import typescript from '@rollup/plugin-typescript'
+import replace from '@rollup/plugin-replace'
+import fs from 'fs'
+
+const defaultOptions = () => ({
+  // additional variables to define with '@rollup/plugin-replace'
+  // e.g. '{ ABC: 123 }' is equivalent to running 'globalThis.ABC = 123'
+  additionalReplacements: {},
+  // additional external dependencies, such as '@bugsnag/browser'
+  external: [],
+  // the entry point for the bundle
+  internal: undefined,
+})
+
+function createRollupConfig (options = defaultOptions()) {
+  const packageJson = JSON.parse(fs.readFileSync(`${process.cwd()}/package.json`))
+
+  return {
+    input: options.internal || 'lib/index.ts',
+    output: {
+      dir: 'dist',
+      format: 'esm',
+      preserveModules: true,
+      generatedCode: {
+        preset: 'es2015',
+      },
+    },
+    external: ['@bugsnag/core'].concat(options.external),
+    plugins: [
+      replace({
+        preventAssignment: true,
+        values: {
+          __VERSION__: packageJson.version,
+          ...options.additionalReplacements,
+        },
+      }),
+      typescript({
+        // don't output anything if there's a TS error
+        noEmitOnError: true,
+        // turn on declaration files and declaration maps
+        compilerOptions: {
+          declaration: true,
+          declarationMap: true,
+          emitDeclarationOnly: true,
+          declarationDir: 'dist/types',
+        },
+      }),
+    ],
+  }
+}
+
+export default createRollupConfig

.rollup/no-tree-shaking.plugin.mjs

@@ -0,0 +1,16 @@
+// when functional components are used in JSX tags, rollup doesn't recognise them as actually being used and tree-shakes them away
+// this plugin prevents that from happening by explicity telling rollup not to tree-shake the module
+function noTreeShakingPlugin(files) {
+    return {
+        name: 'no-treeshaking-plugin',
+        transform(code, id) {
+            for (const file of files) {
+                if (id.indexOf(file) >= 0) {
+                    return { moduleSideEffects: 'no-treeshake' }
+                }
+            }
+        }
+    }
+}
+
+export default noTreeShakingPlugin