Switch over to eslint

.eslintignore

@@ -0,0 +1,3 @@
+/node_modules
+/build
+/dist

.eslintrc.js

@@ -0,0 +1,71 @@
+module.exports = {
+  root: true,
+  env: {
+    browser: true,
+    node: true,
+    es6: true
+  },
+  extends: [
+    'eslint:recommended',
+  ],
+  rules: {
+    "semi": ["warn", "always"],
+    "quotes": ["warn", "double"],
+    "no-constant-condition": ["warn", { checkLoops: false }],
+    "arrow-parens": ["warn", "as-needed"],
+    "curly": ["warn", "multi-line", "consistent"],
+    "indent": ["warn", 2, { SwitchCase: 1 }],
+    "no-console": ["warn", { allow: ["error", "warn"] }],
+    "object-shorthand": ["warn", "always", { avoidQuotes: true }],
+    "quote-props": ["warn", "consistent-as-needed"],
+    "no-useless-rename": "warn",
+    "sort-imports": ["warn", {
+      ignoreDeclarationSort: true
+    }],
+  },
+
+  overrides: [
+    {
+      files: ["rollup.config.js"],
+      parserOptions: { sourceType: "module" },
+    },
+
+    // The default TS config.
+    {
+      files: ["*.ts", "*.tsx"],
+      parser: '@typescript-eslint/parser',
+      parserOptions: { project: "tsconfig.json" },
+      plugins: [
+        '@typescript-eslint',
+      ],
+      extends: [
+        'plugin:@typescript-eslint/eslint-recommended',
+        'plugin:@typescript-eslint/recommended',
+      ],
+      rules: {
+        "@typescript-eslint/member-delimiter-style": ["warn", {
+          multiline: { delimiter: "comma" },
+          singleline: { delimiter: "comma" },
+          overrides: {
+            interface: { multiline: { delimiter: "semi" } },
+          },
+        }],
+        "@typescript-eslint/no-inferrable-types": ["warn", {
+          ignoreParameters: true,
+          ignoreProperties: true,
+        }],
+        "@typescript-eslint/no-empty-function": ["warn", {
+          allow: ["methods"],
+        }],
+        "@typescript-eslint/explicit-function-return-type": "off",
+        "@typescript-eslint/no-non-null-assertion": "off",
+
+        "@typescript-eslint/explicit-member-accessibility": ["warn"],
+
+        // Use Typescript's unused variable warnings instead
+        "@typescript-eslint/no-unused-vars": "off",
+        "@typescript-eslint/no-unused-vars-experimental": "warn",
+      },
+    },
+  ]
+};