Make Keymap class

src/background/infrastructures/ContentMessageListener.ts

@@ -8,6 +8,7 @@ import AddonEnabledController from '../controllers/AddonEnabledController';
 import LinkController from '../controllers/LinkController';
 import OperationController from '../controllers/OperationController';
 import MarkController from '../controllers/MarkController';
+import { toJSON } from '../../shared/Settings';
 
 @injectable()
 export default class ContentMessageListener {
@@ -101,8 +102,8 @@ export default class ContentMessageListener {
     return this.commandController.exec(text);
   }
 
-  onSettingsQuery(): Promise<any> {
-    return this.settingController.getSetting();
+  async onSettingsQuery(): Promise<any> {
+    return toJSON(await this.settingController.getSetting());
   }
 
   onFindGetKeyword(): Promise<string> {

src/background/repositories/SettingRepository.ts

@@ -1,6 +1,6 @@
 import { injectable } from 'tsyringe';
 import MemoryStorage from '../infrastructures/MemoryStorage';
-import Settings from '../../shared/Settings';
+import Settings, { valueOf, toJSON } from '../../shared/Settings';
 import * as PropertyDefs from '../../shared/property-defs';
 
 const CACHED_SETTING_KEY = 'setting';
@@ -14,11 +14,13 @@ export default class SettingRepository {
   }
 
   get(): Promise<Settings> {
-    return Promise.resolve(this.cache.get(CACHED_SETTING_KEY));
+    let data = this.cache.get(CACHED_SETTING_KEY);
+    return Promise.resolve(valueOf(data));
   }
 
   update(value: Settings): void {
-    return this.cache.set(CACHED_SETTING_KEY, value);
+    let data = toJSON(value);
+    return this.cache.set(CACHED_SETTING_KEY, data);
   }
 
   async setProperty(

src/content/client/SettingClient.ts

@@ -1,4 +1,4 @@
-import Settings from '../../shared/Settings';
+import Settings, { valueOf } from '../../shared/Settings';
 import * as messages from '../../shared/messages';
 
 export default interface SettingClient {
@@ -10,6 +10,6 @@ export class SettingClientImpl {
     let settings = await browser.runtime.sendMessage({
       type: messages.SETTINGS_QUERY,
     });
-    return settings as Settings;
+    return valueOf(settings);
   }
 }

src/content/usecases/KeymapUseCase.ts

@@ -3,16 +3,16 @@ import KeymapRepository from '../repositories/KeymapRepository';
 import SettingRepository from '../repositories/SettingRepository';
 import AddonEnabledRepository from '../repositories/AddonEnabledRepository';
 import * as operations from '../../shared/operations';
-import { Keymaps } from '../../shared/Settings';
 import Key from '../domains/Key';
 import KeySequence from '../domains/KeySequence';
+import Keymaps from '../../shared/settings/Keymaps';
 
 type KeymapEntityMap = Map<KeySequence, operations.Operation>;
 
-const reservedKeymaps: Keymaps = {
+const reservedKeymaps = Keymaps.fromJSON({
   '<Esc>': { type: operations.CANCEL },
   '<C-[>': { type: operations.CANCEL },
-};
+});
 
 @injectable()
 export default class KeymapUseCase {
@@ -65,16 +65,11 @@ export default class KeymapUseCase {
   }
 
   private keymapEntityMap(): KeymapEntityMap {
-    let keymaps = {
-      ...this.settingRepository.get().keymaps,
-      ...reservedKeymaps,
-    };
-    let entries = Object.entries(keymaps).map((entry) => {
-      return [
-        KeySequence.fromMapKeys(entry[0]),
-        entry[1],
-      ];
-    }) as [KeySequence, operations.Operation][];
+    let keymaps = this.settingRepository.get().keymaps.combine(reservedKeymaps);
+    let entries = keymaps.entries().map(entry => [
+      KeySequence.fromMapKeys(entry[0]),
+      entry[1],
+    ]) as [KeySequence, operations.Operation][];
     return new Map<KeySequence, operations.Operation>(entries);
   }
 }

src/settings/actions/index.ts

@@ -1,5 +1,5 @@
 import {
-  JSONSettings, FormSettings, SettingSource,
+  JSONTextSettings, FormSettings, SettingSource,
 } from '../../shared/SettingData';
 
 // Settings
@@ -11,14 +11,14 @@ export const SETTING_SWITCH_TO_JSON = 'setting.switch.to.json';
 interface SettingSetSettingsAcion {
   type: typeof SETTING_SET_SETTINGS;
   source: SettingSource;
-  json?: JSONSettings;
+  json?: JSONTextSettings;
   form?: FormSettings;
 }
 
 interface SettingShowErrorAction {
   type: typeof SETTING_SHOW_ERROR;
   error: string;
-  json: JSONSettings;
+  json: JSONTextSettings;
 }
 
 interface SettingSwitchToFormAction {
@@ -28,7 +28,7 @@ interface SettingSwitchToFormAction {
 
 interface SettingSwitchToJsonAction {
   type: typeof SETTING_SWITCH_TO_JSON;
-  json: JSONSettings,
+  json: JSONTextSettings,
 }
 
 export type SettingAction =

src/settings/actions/setting.ts

@@ -1,7 +1,7 @@
 import * as actions from './index';
 import * as storages from '../storage';
 import SettingData, {
-  JSONSettings, FormSettings, SettingSource,
+  JSONTextSettings, FormSettings, SettingSource,
 } from '../../shared/SettingData';
 
 const load = async(): Promise<actions.SettingAction> => {
@@ -26,7 +26,7 @@ const save = async(data: SettingData): Promise<actions.SettingAction> => {
   return set(data);
 };
 
-const switchToForm = (json: JSONSettings): actions.SettingAction => {
+const switchToForm = (json: JSONTextSettings): actions.SettingAction => {
   try {
     // toSettings exercise validation
     let form = FormSettings.fromSettings(json.toSettings());
@@ -44,7 +44,7 @@ const switchToForm = (json: JSONSettings): actions.SettingAction => {
 };
 
 const switchToJson = (form: FormSettings): actions.SettingAction => {
-  let json = JSONSettings.fromSettings(form.toSettings());
+  let json = JSONTextSettings.fromSettings(form.toSettings());
   return {
     type: actions.SETTING_SWITCH_TO_JSON,
     json,

src/settings/components/index.tsx

@@ -8,7 +8,7 @@ import BlacklistForm from './form/BlacklistForm';
 import PropertiesForm from './form/PropertiesForm';
 import * as settingActions from '../../settings/actions/setting';
 import SettingData, {
-  JSONSettings, FormKeymaps, FormSearch, FormSettings,
+  JSONTextSettings, FormKeymaps, FormSearch, FormSettings,
 } from '../../shared/SettingData';
 import { State as AppState } from '../reducers/setting';
 import * as settings from '../../shared/Settings';
@@ -75,7 +75,7 @@ class SettingsComponent extends React.Component<Props> {
     </div>;
   }
 
-  renderJsonFields(json: JSONSettings, error: string) {
+  renderJsonFields(json: JSONTextSettings, error: string) {
     return <div>
       <Input
         type='textarea'
@@ -85,7 +85,7 @@ class SettingsComponent extends React.Component<Props> {
         error={error}
         onValueChange={this.bindJson.bind(this)}
         onBlur={this.save.bind(this)}
-        value={json.toJSON()}
+        value={json.toJSONText()}
       />
     </div>;
   }
@@ -97,7 +97,7 @@ class SettingsComponent extends React.Component<Props> {
       fields = this.renderFormFields(this.props.form);
     } else if (this.props.source === 'json') {
       fields = this.renderJsonFields(
-        this.props.json as JSONSettings, this.props.error);
+        this.props.json as JSONTextSettings, this.props.error);
     }
     return (
       <div>
@@ -165,7 +165,7 @@ class SettingsComponent extends React.Component<Props> {
   bindJson(_name: string, value: string) {
     let data = new SettingData({
       source: this.props.source,
-      json: JSONSettings.valueOf(value),
+      json: JSONTextSettings.fromText(value),
     });
     this.props.dispatch(settingActions.set(data));
   }
@@ -183,7 +183,7 @@ class SettingsComponent extends React.Component<Props> {
         return;
       }
       this.props.dispatch(
-        settingActions.switchToForm(this.props.json as JSONSettings));
+        settingActions.switchToForm(this.props.json as JSONTextSettings));
       this.save();
     }
   }

src/settings/reducers/setting.ts

@@ -1,18 +1,18 @@
 import * as actions from '../actions';
 import {
-  JSONSettings, FormSettings, SettingSource,
+  JSONTextSettings, FormSettings, SettingSource,
 } from '../../shared/SettingData';
 
 export interface State {
   source: SettingSource;
-  json?: JSONSettings;
+  json?: JSONTextSettings;
   form?: FormSettings;
   error: string;
 }
 
 const defaultState: State = {
   source: SettingSource.JSON,
-  json: JSONSettings.valueOf(''),
+  json: JSONTextSettings.fromText(''),
   error: '',
 };
 

src/shared/SettingData.ts

@@ -1,5 +1,6 @@
 import * as operations from './operations';
 import Settings, * as settings from './Settings';
+import Keymaps from './settings/Keymaps';
 
 export class FormKeymaps {
   private data: {[op: string]: string};
@@ -8,8 +9,8 @@ export class FormKeymaps {
     this.data = data;
   }
 
-  toKeymaps(): settings.Keymaps {
-    let keymaps: settings.Keymaps = {};
+  toKeymaps(): Keymaps {
+    let keymaps: { [key: string]: operations.Operation } = {};
     for (let name of Object.keys(this.data)) {
       let [type, argStr] = name.split('?');
       let args = {};
@@ -19,7 +20,7 @@ export class FormKeymaps {
       let key = this.data[name];
       keymaps[key] = operations.valueOf({ type, ...args });
     }
-    return keymaps;
+    return Keymaps.fromJSON(keymaps);
   }
 
   toJSON(): {[op: string]: string} {
@@ -42,10 +43,11 @@ export class FormKeymaps {
     return new FormKeymaps(data);
   }
 
-  static fromKeymaps(keymaps: settings.Keymaps): FormKeymaps {
+  static fromKeymaps(keymaps: Keymaps): FormKeymaps {
+    let json = keymaps.toJSON();
     let data: {[op: string]: string} = {};
-    for (let key of Object.keys(keymaps)) {
-      let op = keymaps[key];
+    for (let key of Object.keys(json)) {
+      let op = json[key];
       let args = { ...op };
       delete args.type;
 
@@ -109,27 +111,32 @@ export class FormSearch {
   }
 }
 
-export class JSONSettings {
-  private json: string;
-
-  constructor(json: any) {
-    this.json = json;
+export class JSONTextSettings {
+  constructor(
+    private json: string,
+  ) {
   }
 
   toSettings(): Settings {
     return settings.valueOf(JSON.parse(this.json));
   }
 
-  toJSON(): string {
+  toJSONText(): string {
     return this.json;
   }
 
-  static valueOf(o: ReturnType<JSONSettings['toJSON']>): JSONSettings {
-    return new JSONSettings(o);
+  static fromText(o: string): JSONTextSettings {
+    return new JSONTextSettings(o);
   }
 
-  static fromSettings(data: Settings): JSONSettings {
-    return new JSONSettings(JSON.stringify(data, undefined, 2));
+  static fromSettings(data: Settings): JSONTextSettings {
+    let json = {
+      keymaps: data.keymaps.toJSON(),
+      search: data.search,
+      properties: data.properties,
+      blacklist: data.blacklist,
+    };
+    return new JSONTextSettings(JSON.stringify(json, undefined, 2));
   }
 }
 
@@ -192,7 +199,7 @@ export class FormSettings {
 
   toSettings(): Settings {
     return settings.valueOf({
-      keymaps: this.keymaps.toKeymaps(),
+      keymaps: this.keymaps.toKeymaps().toJSON(),
       search: this.search.toSearchSettings(),
       properties: this.properties,
       blacklist: this.blacklist,
@@ -244,7 +251,7 @@ export enum SettingSource {
 export default class SettingData {
   private source: SettingSource;
 
-  private json?: JSONSettings;
+  private json?: JSONTextSettings;
 
   private form?: FormSettings;
 
@@ -252,7 +259,7 @@ export default class SettingData {
     source, json, form
   }: {
     source: SettingSource,
-    json?: JSONSettings,
+    json?: JSONTextSettings,
     form?: FormSettings,
   }) {
     this.source = source;
@@ -264,7 +271,7 @@ export default class SettingData {
     return this.source;
   }
 
-  getJSON(): JSONSettings {
+  getJSON(): JSONTextSettings {
     if (!this.json) {
       throw new TypeError('json settings not set');
     }
@@ -283,7 +290,7 @@ export default class SettingData {
     case SettingSource.JSON:
       return {
         source: this.source,
-        json: (this.json as JSONSettings).toJSON(),
+        json: (this.json as JSONTextSettings).toJSONText(),
       };
     case SettingSource.Form:
       return {
@@ -313,8 +320,8 @@ export default class SettingData {
     case SettingSource.JSON:
       return new SettingData({
         source: o.source,
-        json: JSONSettings.valueOf(
-          o.json as ReturnType<JSONSettings['toJSON']>),
+        json: JSONTextSettings.fromText(
+          o.json as ReturnType<JSONTextSettings['toJSONText']>),
       });
     case SettingSource.Form:
       return new SettingData({

src/shared/Settings.ts

@@ -1,7 +1,5 @@
-import * as operations from './operations';
 import * as PropertyDefs from './property-defs';
-
-export type Keymaps = {[key: string]: operations.Operation};
+import Keymaps from './settings/Keymaps';
 
 export interface Search {
   default: string;
@@ -21,14 +19,6 @@ export default interface Settings {
   blacklist: string[];
 }
 
-export const keymapsValueOf = (o: any): Keymaps => {
-  return Object.keys(o).reduce((keymaps: Keymaps, key: string): Keymaps => {
-    let op = operations.valueOf(o[key]);
-    keymaps[key] = op;
-    return keymaps;
-  }, {});
-};
-
 export const searchValueOf = (o: any): Search => {
   if (typeof o.default !== 'string') {
     throw new TypeError('string field "default" not set"');
@@ -97,7 +87,7 @@ export const valueOf = (o: any): Settings => {
   for (let key of Object.keys(o)) {
     switch (key) {
     case 'keymaps':
-      settings.keymaps = keymapsValueOf(o.keymaps);
+      settings.keymaps = Keymaps.fromJSON(o.keymaps);
       break;
     case 'search':
       settings.search = searchValueOf(o.search);
@@ -115,8 +105,17 @@ export const valueOf = (o: any): Settings => {
   return settings;
 };
 
+export const toJSON = (settings: Settings): any => {
+  return {
+    keymaps: settings.keymaps.toJSON(),
+    search: settings.search,
+    properties: settings.properties,
+    blacklist: settings.blacklist,
+  };
+};
+
 export const DefaultSetting: Settings = {
-  keymaps: {
+  keymaps: Keymaps.fromJSON({
     '0': { 'type': 'scroll.home' },
     ':': { 'type': 'command.show' },
     'o': { 'type': 'command.show.open', 'alter': false },
@@ -179,7 +178,7 @@ export const DefaultSetting: Settings = {
     'N': { 'type': 'find.prev' },
     '.': { 'type': 'repeat.last' },
     '<S-Esc>': { 'type': 'addon.toggle.enabled' }
-  },
+  }),
   search: {
     default: 'google',
     engines: {

src/shared/settings/Keymaps.ts

@@ -0,0 +1,37 @@
+import * as operations from '../operations';
+
+export type KeymapsJSON = { [key: string]: operations.Operation };
+
+export default class Keymaps {
+  constructor(
+    private readonly data: KeymapsJSON,
+  ) {
+  }
+
+  static fromJSON(json: any): Keymaps {
+    if (typeof json !== 'object' || json === null) {
+      throw new TypeError('invalid keymaps type: ' + JSON.stringify(json));
+    }
+
+    let data: KeymapsJSON = {};
+    for (let key of Object.keys(json)) {
+      data[key] = operations.valueOf(json[key]);
+    }
+    return new Keymaps(data);
+  }
+
+  combine(other: Keymaps): Keymaps {
+    return new Keymaps({
+      ...this.data,
+      ...other.data,
+    });
+  }
+
+  toJSON(): KeymapsJSON {
+    return this.data;
+  }
+
+  entries(): [string, operations.Operation][] {
+    return Object.entries(this.data);
+  }
+}

test/content/repositories/SettingRepository.test.ts

@@ -1,12 +1,13 @@
 import { SettingRepositoryImpl } from '../../../src/content/repositories/SettingRepository';
 import { expect } from 'chai';
+import Keymaps from '../../../src/shared/settings/Keymaps';
 
 describe('SettingRepositoryImpl', () => {
   it('updates and gets current value', () => {
     let sut = new SettingRepositoryImpl();
 
     let settings = {
-      keymaps: {},
+      keymaps: Keymaps.fromJSON({}),
       search: {
         default: 'google',
         engines: {
@@ -19,7 +20,7 @@ describe('SettingRepositoryImpl', () => {
         complete: 'sbh',
       },
       blacklist: [],
-    }
+    };
 
     sut.set(settings);
 
@@ -27,4 +28,3 @@ describe('SettingRepositoryImpl', () => {
     expect(actual.properties.hintchars).to.equal('abcd1234');
   });
 });
-

test/shared/SettingData.test.ts

@@ -1,8 +1,9 @@
 import SettingData, {
-  FormKeymaps, JSONSettings, FormSettings,
+  FormKeymaps, JSONTextSettings, FormSettings,
 } from '../../src/shared/SettingData';
-import Settings, { Keymaps } from '../../src/shared/Settings';
+import Settings from '../../src/shared/Settings';
 import { expect } from 'chai';
+import Keymaps from '../../src/shared/settings/Keymaps';
 
 describe('shared/SettingData', () => {
   describe('FormKeymaps', () => {
@@ -11,9 +12,9 @@ describe('shared/SettingData', () => {
         let data = {
           'scroll.vertically?{"count":1}': 'j',
           'scroll.home': '0',
-        }
+        };
 
-        let keymaps = FormKeymaps.valueOf(data).toKeymaps();
+        let keymaps = FormKeymaps.valueOf(data).toKeymaps().toJSON();
         expect(keymaps).to.deep.equal({
           'j': { type: 'scroll.vertically', count: 1 },
           '0': { type: 'scroll.home' },
@@ -23,13 +24,13 @@ describe('shared/SettingData', () => {
 
     describe('#fromKeymaps to #toJSON', () => {
       it('create from a Keymaps and create a JSON object', () => {
-        let data: Keymaps = {
+        let keymaps: Keymaps = Keymaps.fromJSON({
           'j': { type: 'scroll.vertically', count: 1 },
           '0': { type: 'scroll.home' },
-        }
+        });
 
-        let keymaps = FormKeymaps.fromKeymaps(data).toJSON();
-        expect(keymaps).to.deep.equal({
+        let form = FormKeymaps.fromKeymaps(keymaps).toJSON();
+        expect(form).to.deep.equal({
           'scroll.vertically?{"count":1}': 'j',
           'scroll.home': '0',
         });
@@ -56,15 +57,20 @@ describe('shared/SettingData', () => {
           "blacklist": []
         }`;
 
-        let settings = JSONSettings.valueOf(o).toSettings();
-        expect(settings).to.deep.equal(JSON.parse(o));
+        let settings = JSONTextSettings.fromText(o).toSettings();
+        expect({
+          keymaps: settings.keymaps.toJSON(),
+          search: settings.search,
+          properties: settings.properties,
+          blacklist: settings.blacklist,
+        }).to.deep.equal(JSON.parse(o));
       });
     });
 
     describe('#fromSettings to #toJSON', () => {
       it('create from a Settings and create a JSON string', () => {
         let o = {
-          keymaps: {},
+          keymaps: Keymaps.fromJSON({}),
           search: {
             default: "google",
             engines: {
@@ -79,8 +85,13 @@ describe('shared/SettingData', () => {
           blacklist: [],
         };
 
-        let json = JSONSettings.fromSettings(o).toJSON();
-        expect(JSON.parse(json)).to.deep.equal(o);
+        let json = JSONTextSettings.fromSettings(o).toJSONText();
+        expect(JSON.parse(json)).to.deep.equal({
+          keymaps: o.keymaps.toJSON(),
+          search: o.search,
+          properties: o.properties,
+          blacklist: o.blacklist,
+        });
       });
     });
   });
@@ -108,7 +119,12 @@ describe('shared/SettingData', () => {
         };
 
         let settings = FormSettings.valueOf(data).toSettings();
-        expect(settings).to.deep.equal({
+        expect({
+          keymaps: settings.keymaps.toJSON(),
+          search: settings.search,
+          properties: settings.properties,
+          blacklist: settings.blacklist,
+        }).to.deep.equal({
           keymaps: {
             'j': { type: 'scroll.vertically', count: 1 },
             '0': { type: 'scroll.home' },
@@ -132,10 +148,10 @@ describe('shared/SettingData', () => {
     describe('#fromSettings to #toJSON', () => {
       it('create from a Settings and create a JSON string', () => {
         let data: Settings = {
-          keymaps: {
+          keymaps: Keymaps.fromJSON({
             'j': { type: 'scroll.vertically', count: 1 },
             '0': { type: 'scroll.home' },
-          },
+          }),
           search: {
             default: "google",
             engines: {

test/shared/Settings.test.ts

@@ -1,31 +1,7 @@
 import * as settings from '../../src/shared/Settings';
-import { expect } from 'chai';
+import {expect} from 'chai';
 
 describe('Settings', () => {
-  describe('#keymapsValueOf', () => {
-    it('returns empty object by empty settings', () => {
-      let keymaps = settings.keymapsValueOf({});
-      expect(keymaps).to.be.empty;
-    });
-
-    it('returns keymaps by valid settings', () => {
-      let keymaps = settings.keymapsValueOf({
-        k: { type: "scroll.vertically", count: -1 },
-        j: { type: "scroll.vertically", count: 1 },
-      });
-
-      expect(keymaps['k']).to.deep.equal({ type: "scroll.vertically", count: -1 });
-      expect(keymaps['j']).to.deep.equal({ type: "scroll.vertically", count: 1 });
-    });
-
-    it('throws a TypeError by invalid settings', () => {
-      expect(() => settings.keymapsValueOf(null)).to.throw(TypeError);
-      expect(() => settings.keymapsValueOf({
-        k: { type: "invalid.operation" },
-      })).to.throw(TypeError);
-    });
-  });
-
   describe('#searchValueOf', () => {
     it('returns search settings by valid settings', () => {
       let search = settings.searchValueOf({
@@ -110,16 +86,6 @@ describe('Settings', () => {
         complete: "sbh"
       });
     });
-
-    it('throws a TypeError by invalid settings', () => {
-      expect(() => settings.keymapsValueOf(null)).to.throw(TypeError);
-      expect(() => settings.keymapsValueOf({
-        smoothscroll: 'false',
-      })).to.throw(TypeError);
-      expect(() => settings.keymapsValueOf({
-        unknown: 'xyz'
-      })).to.throw(TypeError);
-    });
   });
 
   describe('#blacklistValueOf', () => {
@@ -161,7 +127,12 @@ describe('Settings', () => {
         "blacklist": []
       });
 
-      expect(x).to.deep.equal({
+      expect({
+        keymaps: x.keymaps.toJSON(),
+        search: x.search,
+        properties: x.properties,
+        blacklist: x.blacklist,
+      }).to.deep.equal({
         keymaps: {},
         search: {
           default: "google",
@@ -180,7 +151,7 @@ describe('Settings', () => {
 
     it('sets default settings', () => {
       let value = settings.valueOf({});
-      expect(value.keymaps).to.not.be.empty;
+      expect(value.keymaps.toJSON()).to.not.be.empty;
       expect(value.properties).to.not.be.empty;
       expect(value.search.default).to.be.a('string');
       expect(value.search.engines).to.be.an('object');

test/shared/settings/Keymaps.test.ts

@@ -0,0 +1,66 @@
+import Keymaps from '../../../src/shared/settings/Keymaps';
+import { expect } from 'chai';
+
+describe('Keymaps', () => {
+  describe('#valueOf', () => {
+    it('returns empty object by empty settings', () => {
+      let keymaps = Keymaps.fromJSON({}).toJSON();
+      expect(keymaps).to.be.empty;
+    });
+
+    it('returns keymaps by valid settings', () => {
+      let keymaps = Keymaps.fromJSON({
+        k: { type: "scroll.vertically", count: -1 },
+        j: { type: "scroll.vertically", count: 1 },
+      }).toJSON();
+
+      expect(keymaps['k']).to.deep.equal({ type: "scroll.vertically", count: -1 });
+      expect(keymaps['j']).to.deep.equal({ type: "scroll.vertically", count: 1 });
+    });
+
+    it('throws a TypeError by invalid settings', () => {
+      expect(() => Keymaps.fromJSON(null)).to.throw(TypeError);
+      expect(() => Keymaps.fromJSON({
+        k: { type: "invalid.operation" },
+      })).to.throw(TypeError);
+    });
+  });
+
+  describe('#combine', () => {
+    it('returns combined keymaps', () => {
+      let keymaps = Keymaps.fromJSON({
+        k: { type: "scroll.vertically", count: -1 },
+        j: { type: "scroll.vertically", count: 1 },
+      }).combine(Keymaps.fromJSON({
+        n: { type: "find.next" },
+        N: { type: "find.prev" },
+      }));
+
+      let entries = keymaps.entries().sort(([name1], [name2]) => name1.localeCompare(name2));
+      expect(entries).deep.equals([
+        ['j', { type: "scroll.vertically", count: 1 }],
+        ['k', { type: "scroll.vertically", count: -1 }],
+        ['n', { type: "find.next" }],
+        ['N', { type: "find.prev" }],
+      ]);
+    });
+
+    it('overrides current keymaps', () => {
+      let keymaps = Keymaps.fromJSON({
+        k: { type: "scroll.vertically", count: -1 },
+        j: { type: "scroll.vertically", count: 1 },
+      }).combine(Keymaps.fromJSON({
+        n: { type: "find.next" },
+        j: { type: "find.prev" },
+      }));
+
+      let entries = keymaps.entries().sort(([name1], [name2]) => name1.localeCompare(name2));
+      expect(entries).deep.equals([
+        ['j', { type: "find.prev" }],
+        ['k', { type: "scroll.vertically", count: -1 }],
+        ['n', { type: "find.next" }],
+      ]);
+    });
+  });
+});
+