Refactor hash methods to accept callbacks

modules/behavior/hash.js

@@ -5,31 +5,71 @@ import { select as d3_select } from 'd3-selection';
 import { geoSphericalDistance } from '../geo';
 import { modeBrowse } from '../modes/browse';
 import { modeSelect, modeSelectNote } from '../modes';
-import { utilObjectOmit, utilQsString, utilStringQs } from '../util';
+import { utilQsString, utilStringQs } from '../util';
 import { utilArrayIdentical } from '../util/array';
 import { utilDisplayLabel } from '../util/utilDisplayLabel';
 import { localizer, t } from '../core/localizer';
 import { prefs } from '../core/preferences';
 
+function getNewHash(arg) {
+    const original = utilStringQs(window.location.hash);
+    const update = typeof arg === 'function' ? arg(original) : arg;
+    if (!update || typeof update !== 'object') return;
+
+    const updated = { ...original, ...update };
+    Object.keys(update)
+        .filter(key => update[key] === null || update[key] === undefined)
+        .forEach(key => delete updated[key]);
+
+    return '#' + utilQsString(updated, true);
+}
+
+/**
+ * Updates the URL hash by applying a partial patch.
+ *
+ * Keys with nullish values will be removed from the hash.
+ *
+ * @param {(?Object<string, any>|function (Object<string, any>): Object<string, any>)} updater Either
+ * - a plain object of key/value pairs to merge into the hash, or
+ * - a function `(currentHash) => patchObject` that returns such an object.
+ * @returns {boolean} Whether the hash was updated.
+ */
+export function patchHash(updater) {
+    if (!updater || !['function', 'object'].includes(typeof updater)) return false;
+
+    const latestHash = getNewHash(updater);
+    if (!latestHash || window.location.hash === latestHash) return false;
+
+    // Update the URL hash without affecting the browser navigation stack,
+    // though unavoidably creating a browser history entry
+    window.history.replaceState(null, '', latestHash);
+
+    // save last used map location for future
+    const { map } = utilStringQs(latestHash);
+    if (map) prefs('map-location', map);
+    return true;
+}
 
 export function behaviorHash(context) {
 
-    // cached window.location.hash
-    var _cachedHash = null;
     // allowable latitude range
     var _latitudeLimit = 90 - 1e-8;
 
-    function computedHashParameters() {
+    function computeHashUpdate() {
+        if (context.inIntro()) return null;
+
         var map = context.map();
         var center = map.center();
         var zoom = map.zoom();
         var precision = Math.max(0, Math.ceil(Math.log(zoom) / Math.LN2));
-        var oldParams = utilObjectOmit(utilStringQs(window.location.hash),
-            ['comment', 'source', 'hashtags', 'walkthrough']
-        );
-        var newParams = {};
+        const newParams = {
+            comment: null,
+            source: null,
+            hashtags: null,
+            walkthrough: null,
+            id: null
+        };
 
-        delete oldParams.id;
         var selected = context.selectedIDs().filter(function(id) {
             return context.hasEntity(id);
         });
@@ -43,11 +83,7 @@ export function behaviorHash(context) {
             '/' + center[1].toFixed(precision) +
             '/' + center[0].toFixed(precision);
 
-        return Object.assign(oldParams, newParams);
-    }
-
-    function computedHash() {
-        return '#' + utilQsString(computedHashParameters(), true);
+        return newParams;
     }
 
     function computedTitle(includeChangeCount) {
@@ -91,7 +127,7 @@ export function behaviorHash(context) {
         return baseTitle;
     }
 
-    function updateTitle(includeChangeCount) {
+    function updateTitle(includeChangeCount = true) {
         if (!context.setsDocumentTitle()) return;
 
         var newTitle = computedTitle(includeChangeCount);
@@ -100,40 +136,14 @@ export function behaviorHash(context) {
         }
     }
 
-    function updateHashIfNeeded() {
-        if (context.inIntro()) return;
-
-        var latestHash = computedHash();
-        if (_cachedHash !== latestHash) {
-            _cachedHash = latestHash;
-
-            // Update the URL hash without affecting the browser navigation stack,
-            // though unavoidably creating a browser history entry
-            window.history.replaceState(null, '', latestHash);
-
-            // set the title we want displayed for the browser tab/window
-            updateTitle(true /* includeChangeCount */);
-
-            // save last used map location for future
-            const q = utilStringQs(latestHash);
-            if (q.map) {
-                prefs('map-location', q.map);
-            }
-        }
-    }
-
-    var _throttledUpdate = throttle(updateHashIfNeeded, 500);
-    var _throttledUpdateTitle = throttle(function() {
-        updateTitle(true /* includeChangeCount */);
+    var _throttledUpdate = throttle(() => {
+        patchHash(computeHashUpdate);
+        updateTitle();
     }, 500);
+    var _throttledUpdateTitle = throttle(updateTitle, 500);
 
     function hashchange() {
-        // ignore spurious hashchange events
-        if (window.location.hash === _cachedHash) return;
-
-        _cachedHash = window.location.hash;
-
-        var q = utilStringQs(_cachedHash);
+        var q = utilStringQs(window.location.hash);
 
         if (q.theme) {
           context.theme(q.theme);
@@ -147,11 +157,11 @@ export function behaviorHash(context) {
         var mapArgs = (q.map || '').split('/').map(Number);
         if (mapArgs.length < 3 || mapArgs.some(isNaN)) {
             // replace bogus hash
-            updateHashIfNeeded();
-
+            patchHash(computeHashUpdate);
+            updateTitle();
         } else {
             // don't update if the new hash already reflects the state of iD
-            if (_cachedHash === computedHash()) return;
+            if (window.location.hash === getNewHash(computeHashUpdate)) return;
 
             var mode = context.mode();
 
@@ -224,14 +234,14 @@ export function behaviorHash(context) {
             const mapArgs = prefs('map-location').split('/').map(Number);
             context.map().centerZoom([mapArgs[2], Math.min(_latitudeLimit, Math.max(-_latitudeLimit, mapArgs[1]))], mapArgs[0]);
 
-            updateHashIfNeeded();
+            patchHash(computeHashUpdate);
 
             behavior.hadLocation = true;
         }
 
         hashchange();
 
-        updateTitle(false);
+        updateTitle(false /* includeChangeCount */);
     }
 
     behavior.off = function() {

modules/behavior/index.js

@@ -4,7 +4,7 @@ export { behaviorDrag } from './drag';
 export { behaviorDrawWay } from './draw_way';
 export { behaviorDraw } from './draw';
 export { behaviorEdit } from './edit';
-export { behaviorHash } from './hash';
+export { behaviorHash, patchHash } from './hash';
 export { behaviorHover } from './hover';
 export { behaviorLasso } from './lasso';
 export { behaviorOperation } from './operation';

modules/renderer/background.js

@@ -11,8 +11,9 @@ import { fileFetcher } from '../core/file_fetcher';
 import { geoMetersToOffset, geoOffsetToMeters, geoExtent } from '../geo';
 import { rendererBackgroundSource } from './background_source';
 import { rendererTileLayer } from './tile_layer';
-import { utilQsString, utilStringQs } from '../util';
+import { utilStringQs } from '../util';
 import { utilRebind } from '../util/rebind';
+import { patchHash } from '../behavior';
 
 
 let _imageryIndex = null;
@@ -200,32 +201,18 @@ export function rendererBackground(context) {
     const EPSILON = 0.01;
     const x = +meters[0].toFixed(2);
     const y = +meters[1].toFixed(2);
-    let hash = utilStringQs(window.location.hash);
+    const notableOffset = Math.abs(x) > EPSILON || Math.abs(y) > EPSILON;
 
     let id = currSource.id;
     if (id === 'custom') {
       id = `custom:${currSource.template()}`;
     }
 
-    if (id) {
-      hash.background = id;
-    } else {
-      delete hash.background;
-    }
-
-    if (o) {
-      hash.overlays = o;
-    } else {
-      delete hash.overlays;
-    }
-
-    if (Math.abs(x) > EPSILON || Math.abs(y) > EPSILON) {
-      hash.offset = `${x},${y}`;
-    } else {
-      delete hash.offset;
-    }
-
-    window.history.replaceState(null, '', '#' + utilQsString(hash, true));
+    patchHash({
+      background: id || null,
+      overlays: o || null,
+      offset: notableOffset ? `${x},${y}` : null
+    });
 
     let imageryUsed = [];
     let photoOverlaysUsed = [];

modules/renderer/features.js

@@ -4,8 +4,9 @@ import { prefs } from '../core/preferences';
 import { osmEntity } from '../osm';
 import { osmLanduseTags, osmLifecyclePrefixes } from '../osm/tags.js';
 import { utilRebind } from '../util/rebind';
-import { utilArrayGroupBy, utilArrayUnion, utilQsString, utilStringQs } from '../util';
+import { utilArrayGroupBy, utilArrayUnion, utilStringQs } from '../util';
 import { isAddressPoint } from '../svg/labels';
+import { patchHash } from '../behavior';
 
 
 export function rendererFeatures(context) {
@@ -56,15 +57,9 @@ export function rendererFeatures(context) {
 
 
     function update() {
-        const hash = utilStringQs(window.location.hash);
-        const disabled = features.disabled();
-        if (disabled.length) {
-            hash.disable_features = disabled.join(',');
-        } else {
-            delete hash.disable_features;
-        }
-        window.history.replaceState(null, '', '#' + utilQsString(hash, true));
-        prefs('disabled-features', disabled.join(','));
+        const disabled = features.disabled().join(',');
+        patchHash({ disable_features: disabled || null });
+        prefs('disabled-features', disabled);
         _hidden = features.hidden();
         dispatch.call('change');
         dispatch.call('redraw');

modules/renderer/photos.js

@@ -2,7 +2,8 @@ import { dispatch as d3_dispatch } from 'd3-dispatch';
 
 import { services } from '../services';
 import { utilRebind } from '../util/rebind';
-import { utilQsString, utilStringQs } from '../util';
+import { utilStringQs } from '../util';
+import { patchHash } from '../behavior';
 
 
 export function rendererPhotos(context) {
@@ -18,18 +19,12 @@ export function rendererPhotos(context) {
     function photos() {}
 
     function updateStorage() {
-        var hash = utilStringQs(window.location.hash);
         var enabled = context.layers().all().filter(function(d) {
             return _layerIDs.indexOf(d.id) !== -1 && d.layer && d.layer.supported() && d.layer.enabled();
         }).map(function(d) {
             return d.id;
         });
-        if (enabled.length) {
-            hash.photo_overlay = enabled.join(',');
-        } else {
-            delete hash.photo_overlay;
-        }
-        window.history.replaceState(null, '', '#' + utilQsString(hash, true));
+        patchHash({ photo_overlay: enabled.join(',') || null });
     }
 
     /**
@@ -148,15 +143,7 @@ export function rendererPhotos(context) {
      * @param {string} property Name of the value
      */
     function setUrlFilterValue(property, val) {
-        const hash = utilStringQs(window.location.hash);
-        if (val) {
-            if (hash[property] === val) return;
-            hash[property] = val;
-        } else {
-            if (!(property in hash)) return;
-            delete hash[property];
-        }
-        window.history.replaceState(null, '', '#' + utilQsString(hash, true));
+        patchHash({ [property]: val || null });
     }
 
     function showsLayer(id) {

modules/services/kartaview.js

@@ -5,10 +5,11 @@ import { zoom as d3_zoom, zoomIdentity as d3_zoomIdentity } from 'd3-zoom';
 import RBush from 'rbush';
 
 import { geoExtent, geoScaleToZoom } from '../geo';
-import { utilQsString, utilRebind, utilSetTransform, utilStringQs, utilTiler } from '../util';
+import { utilQsString, utilRebind, utilSetTransform, utilTiler } from '../util';
 import { services } from './';
 import { searchLimited } from '../util/partition';
 import { localeDateString } from '../util/date';
+import { patchHash } from '../behavior';
 
 
 var apibase = 'https://kartaview.org';
@@ -363,7 +364,7 @@ export default {
     hideViewer: function(context) {
         _oscSelectedImage = null;
 
-        this.updateUrlImage(null);
+        patchHash({ photo: null });
 
         var viewer = context.container().select('.photoviewer');
         if (!viewer.empty()) viewer.datum(null);
@@ -386,7 +387,7 @@ export default {
 
         _oscSelectedImage = d;
 
-        this.updateUrlImage(imageKey);
+        patchHash({ photo: 'kartaview/' + imageKey });
 
         var viewer = context.container().select('.photoviewer');
         if (!viewer.empty()) viewer.datum(d);
@@ -517,17 +518,6 @@ export default {
     },
 
 
-    updateUrlImage: function(imageKey) {
-        const hash = utilStringQs(window.location.hash);
-        if (imageKey) {
-            hash.photo = 'kartaview/' + imageKey;
-        } else {
-            delete hash.photo;
-        }
-        window.history.replaceState(null, '', '#' + utilQsString(hash, true));
-    },
-
-
     cache: function() {
         return _oscCache;
     }