add timeformatter, shared between all view models

src/domain/ViewModel.ts

@@ -29,6 +29,7 @@ import type {ILogger} from "../logging/types";
 import type {Navigation} from "./navigation/Navigation";
 import type {SegmentType} from "./navigation/index";
 import type {IURLRouter} from "./navigation/URLRouter";
+import type { ITimeFormatter } from "../platform/types/types";
 
 export type Options<T extends object = SegmentType> = {
     platform: Platform;
@@ -145,4 +146,8 @@ export class ViewModel<N extends object = SegmentType, O extends Options<N> = Op
         // typescript needs a little help here
         return this._options.navigation as unknown as Navigation<N>;
     }
+
+    get timeFormatter(): ITimeFormatter {
+        return this._options.platform.timeFormatter;
+    }
 }

src/domain/session/room/timeline/tiles/DateTile.ts

@@ -48,13 +48,7 @@ export class DateTile extends ViewModel implements ITile<BaseEventEntry> {
 
     get date(): string {
         if (!this._dateString) {
-            const date = new Date(this.refEntry.timestamp);
-            this._dateString = date.toLocaleDateString({}, {
-                weekday: 'long',
-                year: 'numeric',
-                month: 'long',
-                day: 'numeric'
-            });
+            this._dateString = this.timeFormatter.formatRelativeDate(new Date(this.refEntry.timestamp));
         }
         return this._dateString;
     }

src/platform/types/types.ts

@@ -16,7 +16,7 @@ limitations under the License.
 
 import type {RequestResult} from "../web/dom/request/fetch.js";
 import type {RequestBody} from "../../matrix/net/common";
-import type {ILogItem} from "../../logging/types";
+import type { BaseObservableValue } from "../../observable/ObservableValue";
 
 export interface IRequestOptions {
     uploadProgress?: (loadedBytes: number) => void;
@@ -43,3 +43,7 @@ export type File = {
     readonly name: string;
     readonly blob: IBlobHandle;
 }
+
+export interface ITimeFormatter {
+    formatRelativeDate(date: Date): string;
+}

src/platform/web/Platform.js

@@ -39,6 +39,7 @@ import {Disposables} from "../../utils/Disposables";
 import {parseHTML} from "./parsehtml.js";
 import {handleAvatarError} from "./ui/avatar";
 import {ThemeLoader} from "./theming/ThemeLoader";
+import {TimeFormatter} from "./dom/TimeFormatter";
 
 function addScript(src) {
     return new Promise(function (resolve, reject) {
@@ -139,6 +140,7 @@ export class Platform {
         this._createLogger(options?.development);
         this.history = new History();
         this.onlineStatus = new OnlineStatus();
+        this.timeFormatter = new TimeFormatter();
         this._serviceWorkerHandler = null;
         if (assetPaths.serviceWorker && "serviceWorker" in navigator) {
             this._serviceWorkerHandler = new ServiceWorkerHandler();

src/platform/web/dom/TimeFormatter.ts

@@ -0,0 +1,73 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import type { ITimeFormatter } from "../../types/types";
+import {Clock} from "./Clock";
+
+enum TimeScope {
+    Minute = 60 * 1000,
+    Day = 24 * 60 * 60 * 1000,
+}
+
+export class TimeFormatter implements ITimeFormatter {
+
+    private todayMidnight: Date;
+    private relativeDayFormatter: Intl.RelativeTimeFormat;
+    private weekdayFormatter: Intl.DateTimeFormat;
+    private currentYearFormatter: Intl.DateTimeFormat;
+    private otherYearFormatter: Intl.DateTimeFormat;
+
+    constructor(private clock: Clock) {
+        // don't use the clock time here as the DOM relative formatters don't support setting the reference date anyway
+        this.todayMidnight = new Date();
+        this.todayMidnight.setHours(0, 0, 0, 0);
+        this.relativeDayFormatter = new Intl.RelativeTimeFormat(undefined, {numeric: "auto"});
+        this.weekdayFormatter = new Intl.DateTimeFormat(undefined, {weekday: 'long'});
+        this.currentYearFormatter = new Intl.DateTimeFormat(undefined, {
+            weekday: 'long',
+            month: 'long',
+            day: 'numeric'
+        });
+        this.otherYearFormatter = new Intl.DateTimeFormat(undefined, {
+            weekday: 'long',
+            year: 'numeric',
+            month: 'long',
+            day: 'numeric'
+        });
+    }
+
+    formatRelativeDate(date: Date): string {
+        let daysDiff = Math.floor((date.getTime() - this.todayMidnight.getTime()) / TimeScope.Day);
+        console.log("formatRelativeDate daysDiff", daysDiff, date);
+        if (daysDiff >= -1 && daysDiff <= 1) {
+            // Tomorrow, Today, Yesterday
+            return capitalizeFirstLetter(this.relativeDayFormatter.format(daysDiff, "day"));
+        } else if (daysDiff > -7 && daysDiff < 0) {
+            // Wednesday
+            return this.weekdayFormatter.format(date);
+        } else if (this.todayMidnight.getFullYear() === date.getFullYear()) {
+            // Friday, November 6
+            return this.currentYearFormatter.format(date);
+        } else {
+            // Friday, November 5, 2021
+            return this.otherYearFormatter.format(date);
+        }
+    }
+}
+
+function capitalizeFirstLetter(str: string) {
+    return str.slice(0, 1).toLocaleUpperCase() + str.slice(1);
+}