6 files changed, 21 insertions, 8 deletions
diff --git a/e2e/settings.js b/e2e/settings.js
index b69e3e7..e78add0 100644
--- a/e2e/settings.js
+++ b/e2e/settings.js
@@ -24,7 +24,7 @@ module.exports = {
     "G": { "type": "scroll.bottom" },
     "$": { "type": "scroll.end" },
     "d": { "type": "tabs.close" },
-    "D": { "type": "tabs.close", "selectLeft": true },
+    "D": { "type": "tabs.close", "select": "left" },
     "x$": { "type": "tabs.close.right" },
     "!d": { "type": "tabs.close.force" },
     "u": { "type": "tabs.reopen" },
diff --git a/src/background/controllers/OperationController.ts b/src/background/controllers/OperationController.ts
index 9480ed5..7a10ad6 100644
--- a/src/background/controllers/OperationController.ts
+++ b/src/background/controllers/OperationController.ts
@@ -32,7 +32,7 @@ export default class OperationController {
   doOperation(operation: operations.Operation): Promise<any> {
     switch (operation.type) {
     case operations.TAB_CLOSE:
-      return this.tabUseCase.close(false, operation.selectLeft);
+      return this.tabUseCase.close(false, operation.select === 'left');
     case operations.TAB_CLOSE_RIGHT:
       return this.tabUseCase.closeRight();
     case operations.TAB_CLOSE_FORCE:
diff --git a/src/settings/keymaps.ts b/src/settings/keymaps.ts
index b9a08e6..24ba1a5 100644
--- a/src/settings/keymaps.ts
+++ b/src/settings/keymaps.ts
@@ -18,7 +18,7 @@ const fields = [
     ['mark.set.prefix', 'Set mark at current position'],
     ['mark.jump.prefix', 'Jump to the mark'],
   ], [
-    ['tabs.close?{"selectLeft":false}', 'Close a tab'],
+    ['tabs.close?{"select":"right"}', 'Close a tab'],
     ['tabs.close.right', 'Close all tabs to the right'],
     ['tabs.reopen', 'Reopen closed tab'],
     ['tabs.next', 'Select next tab'],
diff --git a/src/shared/SettingData.ts b/src/shared/SettingData.ts
index e6434a2..14a7d35 100644
--- a/src/shared/SettingData.ts
+++ b/src/shared/SettingData.ts
@@ -353,7 +353,7 @@ export const DefaultSettingData: SettingData = SettingData.valueOf({
     "G": { "type": "scroll.bottom" },
     "$": { "type": "scroll.end" },
     "d": { "type": "tabs.close" },
-    "D": { "type": "tabs.close", "selectLeft": true },
+    "D": { "type": "tabs.close", "select": "left" },
     "x$": { "type": "tabs.close.right" },
     "!d": { "type": "tabs.close.force" },
     "u": { "type": "tabs.reopen" },
diff --git a/src/shared/Settings.ts b/src/shared/Settings.ts
index 19101c1..2a392df 100644
--- a/src/shared/Settings.ts
+++ b/src/shared/Settings.ts
@@ -146,7 +146,7 @@ export const DefaultSetting: Settings = {
     'G': { 'type': 'scroll.bottom' },
     '$': { 'type': 'scroll.end' },
     'd': { 'type': 'tabs.close' },
-    'D': { 'type': 'tabs.close', 'selectLeft': true },
+    'D': { 'type': 'tabs.close', 'select': 'left' },
     'x$': { 'type': 'tabs.close.right' },
     '!d': { 'type': 'tabs.close.force' },
     'u': { 'type': 'tabs.reopen' },
diff --git a/src/shared/operations.ts b/src/shared/operations.ts
index f657db1..2df2e67 100644
--- a/src/shared/operations.ts
+++ b/src/shared/operations.ts
@@ -201,7 +201,7 @@ export interface PageHomeOperation {
 
 export interface TabCloseOperation {
   type: typeof TAB_CLOSE;
-  selectLeft?: boolean;
+  select?: 'left' | 'right';
 }
 
 export interface TabCloseForceOperation {
@@ -372,6 +372,19 @@ const assertOptionalBoolean = (obj: any, name: string) => {
   }
 };
 
+const assertOptionalString = (obj: any, name: string, values?: string[]) => {
+  if (Object.prototype.hasOwnProperty.call(obj, name)) {
+    let value = obj[name];
+    if (typeof value !== 'string') {
+      throw new TypeError(`Not a string parameter: '${name}'`);
+    }
+    if (values && values.length && values.indexOf(value) === -1) {
+      // eslint-disable-next-line max-len
+      throw new TypeError(`Invalid parameter for '${name}': '${value}'`);
+    }
+  }
+};
+
 const assertRequiredNumber = (obj: any, name: string) => {
   if (!Object.prototype.hasOwnProperty.call(obj, name) ||
     typeof obj[name] !== 'number') {
@@ -418,10 +431,10 @@ export const valueOf = (o: any): Operation => {
       newTab: Boolean(typeof o.newTab === undefined ? false : o.newTab),
     };
   case TAB_CLOSE:
-    assertOptionalBoolean(o, 'selectLeft');
+    assertOptionalString(o, 'select', ['left', 'right']);
     return {
       type: TAB_CLOSE,
-      selectLeft: Boolean(typeof o.selectLeft === undefined ? false : o.selectLeft), // eslint-disable-line max-len
+      select: (typeof o.select === undefined ? 'right' : o.select),
     };
   case TAB_RELOAD:
     assertOptionalBoolean(o, 'cache');