3 files changed, 29 insertions, 8 deletions
diff --git a/src/shared/SettingData.ts b/src/shared/SettingData.ts
index 1c085cf..14a7d35 100644
--- a/src/shared/SettingData.ts
+++ b/src/shared/SettingData.ts
@@ -353,7 +353,8 @@ export const DefaultSettingData: SettingData = SettingData.valueOf({
     "G": { "type": "scroll.bottom" },
     "$": { "type": "scroll.end" },
     "d": { "type": "tabs.close" },
-    "D": { "type": "tabs.close.right" },
+    "D": { "type": "tabs.close", "select": "left" },
+    "x$": { "type": "tabs.close.right" },
     "!d": { "type": "tabs.close.force" },
     "u": { "type": "tabs.reopen" },
     "K": { "type": "tabs.prev" },
diff --git a/src/shared/Settings.ts b/src/shared/Settings.ts
index 0bef342..2a392df 100644
--- a/src/shared/Settings.ts
+++ b/src/shared/Settings.ts
@@ -146,7 +146,8 @@ export const DefaultSetting: Settings = {
     'G': { 'type': 'scroll.bottom' },
     '$': { 'type': 'scroll.end' },
     'd': { 'type': 'tabs.close' },
-    'D': { 'type': 'tabs.close.right' },
+    'D': { 'type': 'tabs.close', 'select': 'left' },
+    'x$': { 'type': 'tabs.close.right' },
     '!d': { 'type': 'tabs.close.force' },
     'u': { 'type': 'tabs.reopen' },
     'K': { 'type': 'tabs.prev' },
diff --git a/src/shared/operations.ts b/src/shared/operations.ts
index 2b03d9d..2df2e67 100644
--- a/src/shared/operations.ts
+++ b/src/shared/operations.ts
@@ -201,6 +201,7 @@ export interface PageHomeOperation {
 
 export interface TabCloseOperation {
   type: typeof TAB_CLOSE;
+  select?: 'left' | 'right';
 }
 
 export interface TabCloseForceOperation {
@@ -367,28 +368,41 @@ export type Operation =
 const assertOptionalBoolean = (obj: any, name: string) => {
   if (Object.prototype.hasOwnProperty.call(obj, name) &&
       typeof obj[name] !== 'boolean') {
-    throw new TypeError(`Not a boolean parameter '${name}'`);
+    throw new TypeError(`Not a boolean parameter: '${name}'`);
+  }
+};
+
+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') {
-    throw new TypeError(`Missing number parameter '${name}`);
+    throw new TypeError(`Missing number parameter: '${name}`);
   }
 };
 
 const assertRequiredString = (obj: any, name: string) => {
   if (!Object.prototype.hasOwnProperty.call(obj, name) ||
     typeof obj[name] !== 'string') {
-    throw new TypeError(`Missing string parameter '${name}`);
+    throw new TypeError(`Missing string parameter: '${name}`);
   }
 };
 
 // eslint-disable-next-line complexity, max-lines-per-function
 export const valueOf = (o: any): Operation => {
   if (!Object.prototype.hasOwnProperty.call(o, 'type')) {
-    throw new TypeError(`missing 'type' field`);
+    throw new TypeError(`Missing 'type' field`);
   }
   switch (o.type) {
   case COMMAND_SHOW_OPEN:
@@ -416,6 +430,12 @@ export const valueOf = (o: any): Operation => {
       type: PAGE_HOME,
       newTab: Boolean(typeof o.newTab === undefined ? false : o.newTab),
     };
+  case TAB_CLOSE:
+    assertOptionalString(o, 'select', ['left', 'right']);
+    return {
+      type: TAB_CLOSE,
+      select: (typeof o.select === undefined ? 'right' : o.select),
+    };
   case TAB_RELOAD:
     assertOptionalBoolean(o, 'cache');
     return {
@@ -458,7 +478,6 @@ export const valueOf = (o: any): Operation => {
   case NAVIGATE_ROOT:
   case FOCUS_INPUT:
   case PAGE_SOURCE:
-  case TAB_CLOSE:
   case TAB_CLOSE_FORCE:
   case TAB_CLOSE_RIGHT:
   case TAB_REOPEN:
@@ -483,5 +502,5 @@ export const valueOf = (o: any): Operation => {
   case REPEAT_LAST:
     return { type: o.type };
   }
-  throw new TypeError('unknown operation type: ' + o.type);
+  throw new TypeError('Unknown operation type: ' + o.type);
 };