narrow [nfc]: Combine 1:1 and group PMs as a single case in caseNarrow.

Most call sites get simpler, because they were already doing the
same thing in the two cases.

src/chat/narrowsSelectors.js

@@ -152,8 +152,7 @@ export const isNarrowValid: Selector<boolean, Narrow> = createSelector(
       {
         stream: streamName => streams.find(s => s.name === streamName) !== undefined,
         topic: streamName => streams.find(s => s.name === streamName) !== undefined,
-        pm: email => allUsersByEmail.get(email) !== undefined,
-        groupPm: emails => emails.every(email => allUsersByEmail.get(email) !== undefined),
+        pm: emails => emails.every(email => allUsersByEmail.get(email) !== undefined),
       },
       () => true,
     ),

src/outbox/outboxActions.js

@@ -122,15 +122,13 @@ const extractTypeToAndSubjectFromNarrow = (
   narrow: Narrow,
   allUsersByEmail: Map<string, UserOrBot>,
   ownUser: UserOrBot,
-): DataFromNarrow => {
-  const forPm = emails => ({
-    type: 'private',
-    display_recipient: mapEmailsToUsers(emails, allUsersByEmail, ownUser),
-    subject: '',
-  });
-  return caseNarrowPartial(narrow, {
-    pm: email => forPm([email]),
-    groupPm: forPm,
+): DataFromNarrow =>
+  caseNarrowPartial(narrow, {
+    pm: emails => ({
+      type: 'private',
+      display_recipient: mapEmailsToUsers(emails, allUsersByEmail, ownUser),
+      subject: '',
+    }),
 
     // TODO: we shouldn't ever be passing a whole-stream narrow here;
     //   ensure we don't, then remove this case
@@ -142,7 +140,6 @@ const extractTypeToAndSubjectFromNarrow = (
       subject: topic,
     }),
   });
-};
 
 const getContentPreview = (content: string, state: GlobalState): string => {
   try {

src/title/Title.js

@@ -30,8 +30,12 @@ export default class Title extends PureComponent<Props> {
       allPrivate: () => <TitleSpecial code="private" color={color} />,
       stream: () => <TitleStream narrow={narrow} color={color} />,
       topic: () => <TitleStream narrow={narrow} color={color} />,
-      pm: email => <TitlePrivate email={email} color={color} />,
-      groupPm: () => <TitleGroup narrow={narrow} />,
+      pm: emails =>
+        emails.length === 1 ? (
+          <TitlePrivate email={emails[0]} color={color} />
+        ) : (
+          <TitleGroup narrow={narrow} />
+        ),
       search: () => null,
     });
   }

src/users/usersActions.js

@@ -66,8 +66,7 @@ export const sendTypingStart = (narrow: Narrow) => async (
 
   const usersByEmail = getAllUsersByEmail(getState());
   const recipientIds = caseNarrowPartial(narrow, {
-    pm: email => [email],
-    groupPm: emails => emails,
+    pm: emails => emails,
   }).map(email => {
     const user = usersByEmail.get(email);
     if (!user) {

src/utils/narrow.js

@@ -127,8 +127,7 @@ export const SEARCH_NARROW = (query: string): Narrow => [
 
 type NarrowCases<T> = {|
   home: () => T,
-  pm: (email: string) => T,
-  groupPm: (emails: string[]) => T,
+  pm: (emails: string[]) => T,
   starred: () => T,
   mentioned: () => T,
   allPrivate: () => T,
@@ -147,12 +146,9 @@ export function caseNarrow<T>(narrow: Narrow, cases: NarrowCases<T>): T {
     case 0: return cases.home();
     case 1:
       switch (narrow[0].operator) {
-        case 'pm-with':
-          if (narrow[0].operand.indexOf(',') < 0) {
-            return cases.pm(narrow[0].operand);
-          } else { /* eslint-disable-line */
+        case 'pm-with': {
             const emails = narrow[0].operand.split(',');
-            return cases.groupPm(emails);
+            return cases.pm(emails);
           }
         case 'is':
           switch (narrow[0].operand) {
@@ -180,7 +176,6 @@ export function caseNarrowPartial<T>(narrow: Narrow, cases: $Shape<NarrowCases<T
       ({
         home: err('home'),
         pm: err('PM'),
-        groupPm: err('group PM'),
         starred: err('starred'),
         mentioned: err('mentions'),
         allPrivate: err('all-private'),
@@ -204,7 +199,6 @@ export function caseNarrowDefault<T>(
       ({
         home: defaultCase,
         pm: defaultCase,
-        groupPm: defaultCase,
         starred: defaultCase,
         mentioned: defaultCase,
         allPrivate: defaultCase,
@@ -221,10 +215,10 @@ export const isHomeNarrow = (narrow?: Narrow): boolean =>
   !!narrow && caseNarrowDefault(narrow, { home: () => true }, () => false);
 
 export const is1to1PmNarrow = (narrow?: Narrow): boolean =>
-  !!narrow && caseNarrowDefault(narrow, { pm: () => true }, () => false);
+  !!narrow && caseNarrowDefault(narrow, { pm: emails => emails.length === 1 }, () => false);
 
 export const isGroupPmNarrow = (narrow?: Narrow): boolean =>
-  !!narrow && caseNarrowDefault(narrow, { groupPm: () => true }, () => false);
+  !!narrow && caseNarrowDefault(narrow, { pm: emails => emails.length > 1 }, () => false);
 
 /**
  * The recipients' emails if a group PM narrow; else error.
@@ -233,10 +227,17 @@ export const isGroupPmNarrow = (narrow?: Narrow): boolean =>
  * to use caseNarrow.
  */
 export const emailsOfGroupPmNarrow = (narrow: Narrow): string[] =>
-  caseNarrowPartial(narrow, { groupPm: emails => emails });
+  caseNarrowPartial(narrow, {
+    pm: emails => {
+      if (emails.length === 1) {
+        throw new Error('emailsOfGroupPmNarrow: got 1:1 narrow');
+      }
+      return emails;
+    },
+  });
 
 export const isPmNarrow = (narrow?: Narrow): boolean =>
-  !!narrow && caseNarrowDefault(narrow, { pm: () => true, groupPm: () => true }, () => false);
+  !!narrow && caseNarrowDefault(narrow, { pm: () => true }, () => false);
 
 export const isSpecialNarrow = (narrow?: Narrow): boolean =>
   !!narrow
@@ -277,39 +278,34 @@ export const isMessageInNarrow = (
   flags: $ReadOnlyArray<string>,
   narrow: Narrow,
   ownEmail: string,
-): boolean => {
-  const matchPmRecipients = (emails: string[]) => {
-    if (message.type !== 'private') {
-      return false;
-    }
-    const recipients = recipientsOfPrivateMessage(message);
-    const narrowAsRecipients = emails.map(email => ({ email }));
-    return (
-      normalizeRecipientsSansMe(recipients, ownEmail)
-      === normalizeRecipientsSansMe(narrowAsRecipients, ownEmail)
-    );
-  };
-
-  return caseNarrow(narrow, {
+): boolean =>
+  caseNarrow(narrow, {
     home: () => true,
     stream: name => message.type === 'stream' && name === streamNameOfStreamMessage(message),
     topic: (streamName, topic) =>
       message.type === 'stream'
       && streamName === streamNameOfStreamMessage(message)
       && topic === message.subject,
-    pm: email => matchPmRecipients([email]),
-    groupPm: matchPmRecipients,
+    pm: emails => {
+      if (message.type !== 'private') {
+        return false;
+      }
+      const recipients = recipientsOfPrivateMessage(message);
+      const narrowAsRecipients = emails.map(email => ({ email }));
+      return (
+        normalizeRecipientsSansMe(recipients, ownEmail)
+        === normalizeRecipientsSansMe(narrowAsRecipients, ownEmail)
+      );
+    },
     starred: () => flags.includes('starred'),
     mentioned: () => flags.includes('mentioned') || flags.includes('wildcard_mentioned'),
     allPrivate: () => message.type === 'private',
     search: () => false,
   });
-};
 
 export const canSendToNarrow = (narrow: Narrow): boolean =>
   caseNarrow(narrow, {
     pm: () => true,
-    groupPm: () => true,
     stream: () => true,
     topic: () => true,
     home: () => false,

src/webview/html/messageHeaderAsHtml.js

@@ -34,7 +34,6 @@ export default (
     topic: () => 'none',
 
     pm: () => 'none',
-    groupPm: () => 'none',
 
     home: () => 'full',
     starred: () => 'full',