add setting validator

src/shared/validators/setting.js

@@ -0,0 +1,33 @@
+import operations from '../../operations';
+
+const VALID_TOP_KEYS = ['keymaps'];
+const VALID_OPERATION_VALUES = Object.keys(operations).map((key) => {
+  return operations[key];
+});
+
+const validateInvalidTopKeys = (settings) => {
+  let invalidKey = Object.keys(settings).find((key) => {
+    return !VALID_TOP_KEYS.includes(key);
+  });
+  if (invalidKey) {
+    throw Error(`Unknown key: "${invalidKey}"`);
+  }
+};
+
+const validateKeymaps = (keymaps) => {
+  for (let key of Object.keys(keymaps)) {
+    let value = keymaps[key];
+    if (!VALID_OPERATION_VALUES.includes(value.type)) {
+      throw Error(`Unknown operation: "${value.type}"`);
+    }
+  }
+};
+
+const validate = (settings) => {
+  validateInvalidTopKeys(settings);
+  if (settings.keymaps) {
+    validateKeymaps(settings.keymaps);
+  }
+};
+
+export { validate };

test/shared/validators/setting.test.js

@@ -0,0 +1,25 @@
+import { expect } from "chai";
+import { validate } from '../../../src/shared/validators/setting';
+
+describe("setting validator", () => {
+  describe("unknown top keys", () => {
+    it('throws an error for unknown settings', () => {
+      let settings = { keymaps: {}, poison: 123 };
+      let fn = validate.bind(undefined, settings)
+      expect(fn).to.throw(Error, 'poison');
+    })
+  });
+
+  describe("keymaps settings", () => {
+    it('throws an error for unknown operation', () => {
+      let settings = {
+        keymaps: {
+          a: { 'type': 'scroll.home' },
+          b: { 'type': 'poison.dressing' },
+        }
+      };
+      let fn = validate.bind(undefined, settings)
+      expect(fn).to.throw(Error, 'poison.dressing');
+    });
+  });
+});