# BaseSessionModel

Auto-generated @jbrowse/mobx-state-tree API for the current JBrowse release —
see [pluggable elements](https://jbrowse.org/jb2-staging/docs/developer_guide/) for concepts. Built into
JBrowse core.
[View source](https://github.com/GMOD/jbrowse-components/blob/main/packages/product-core/src/Session/BaseSession.ts).

base session shared by all JBrowse products. Be careful what you include here,
everything will use it.

Members a composed model contributes are listed here too, so these tables are
the whole surface.

## Properties

<!-- prettier-ignore -->
| Member | Description |
| --- | --- |
| <span id="property-id">**id**</span><br><code>id: ElementId</code> |  |
| <span id="property-name">**name**</span><br><code>name: types.string</code> |  |
| <span id="property-focusedviewid">**focusedViewId**</span><br><code>focusedViewId: types.maybe(types.string)</code> | used to keep track of which view is in focus |
| <span id="property-highlightsvisible">**highlightsVisible**</span><br><code>highlightsVisible: types.stripDefault(types.boolean, true)</code> | one session-wide toggle for all region highlight bands (URL/view highlights and bookmark overlays) |

## Volatiles

<!-- prettier-ignore -->
| Member | Description | Defined by |
| --- | --- | --- |
| <span id="volatile-selection">**selection**</span><br><code>selection: undefined as unknown</code> | this is the globally "selected" object. can be anything. code that wants to deal with this should examine it to see what kind of thing it is. | BaseSessionModel |
| <span id="volatile-hovered">**hovered**</span><br><code>hovered: undefined as unknown</code> | this is the globally "hovered" object. can be anything. code that wants to deal with this should examine it to see what kind of thing it is. | BaseSessionModel |
| <span id="volatile-queueofdialogs">**queueOfDialogs**</span><br><span class="cell-more"><button type="button" class="cell-more-trigger"><code>queueOfDialogs: [] as [DialogComponentType, Record&lt;string, unkn…</code></button><dialog class="cell-dialog"><form method="dialog"><button class="cell-dialog-close" aria-label="Close">✕</button></form><pre><code>queueOfDialogs: [] as [DialogComponentType, Record&lt;string, unknown&gt;][]</code></pre></dialog></span> |  | BaseSessionModel |
| <span id="volatile-preferencesoverrides">**preferencesOverrides**</span><br><span class="cell-more"><button type="button" class="cell-more-trigger"><code>preferencesOverrides: observable.map&lt;string, unknown&gt;(undefined…</code></button><dialog class="cell-dialog"><form method="dialog"><button class="cell-dialog-close" aria-label="Close">✕</button></form><pre><code>preferencesOverrides: observable.map&lt;string, unknown&gt;(undefined, {&#10;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;deep: false,&#10;&#160;&#160;&#160;&#160;&#160;&#160;})</code></pre></dialog></span> | runtime user-preference overrides keyed by preference id, resolved by `getPreference` against the `configuration.preferences` admin defaults. Empty here (config-only); products that let users edit preferences load and persist these via localStorage. A runtime override map layered over config defaults, kept off the snapshot since prefs are local UI.<br><br>An `observable.map` (not a plain object reassigned wholesale) so each preference is its own tracked key: writing one (`setScrollZoom`) can't invalidate a reader of another (`getDisplayTypeDefault` in a track's `rpcProps`). A single spread-replaced object made every setter wake every reader, so toggling scroll-to-zoom re-fetched every track. For the same reason each promoted per-display-type default is a flat composite key (see `displayTypeDefaultKey`), not a single nested `displayTypeDefaults` object — promoting one default can't wake readers of a different one.<br><br>`deep: false` is load-bearing, not a micro-optimization. The default enhancer wraps an object/array value in a MobX Proxy on `set`, and a promoted default is handed straight back out by `getConf` — so an object-valued promotable slot (alignments `colorBy`) put a Proxy into `rpcProps()`, and V8's structured-clone serializer rejects a Proxy: `worker.postMessage` threw `DataCloneError` on the next fetch of any track following that default (electron IPC and `structuredClone` in the share bake likewise). The map still notifies per key on `set`, so shallow values lose no reactivity — and nothing can mutate a preference in place, because `setPreferenceOverride` freezes what it stores. | BaseSessionModel |
| <span id="volatile-snackbarmessages">**snackbarMessages**</span><br><code>snackbarMessages: observable.array&lt;SnackbarMessage&gt;()</code> |  | [SnackbarModel](../snackbarmodel#volatile-snackbarmessages) |
| <span id="volatile-errordialog">**errorDialog**</span><br><code>errorDialog: undefined as ErrorDialogState &#124; undefined</code> | <span data-pagefind-ignore>the error currently shown in the stack-trace dialog. Kept off the dialog queue so it can stack on top of an already-open dialog (e.g. the one whose action raised the error) instead of waiting behind it</span> | [SnackbarModel](../snackbarmodel#volatile-errordialog) |

## Getters

<!-- prettier-ignore -->
| Member | Description | Defined by |
| --- | --- | --- |
| <span id="getter-root">**root**</span><br><code>TypeOrStateTreeNodeToStateTreeNode&lt;ROOT_MODEL_TYPE&gt;</code> |  | BaseSessionModel |
| <span id="getter-jbrowse">**jbrowse**</span><br><code>any</code> |  | BaseSessionModel |
| <span id="getter-rpcmanager">**rpcManager**</span><br><code>RpcManager</code> |  | BaseSessionModel |
| <span id="getter-configuration">**configuration**</span><br><code>Instance&lt;JB_CONFIG_SCHEMA&gt;</code> |  | BaseSessionModel |
| <span id="getter-adminmode">**adminMode**</span><br><code>boolean</code> |  | BaseSessionModel |
| <span id="getter-textsearchmanager">**textSearchManager**</span><br><code>TextSearchManager</code> |  | BaseSessionModel |
| <span id="getter-assemblies">**assemblies**</span><br><span class="cell-more"><button type="button" class="cell-more-trigger"><code>(ModelInstanceTypeProps&lt;…&gt; &amp; { setSubschema(slotName: string, d…</code></button><dialog class="cell-dialog"><form method="dialog"><button class="cell-dialog-close" aria-label="Close">✕</button></form><pre><code>(ModelInstanceTypeProps&lt;…&gt; &amp; { setSubschema(slotName: string, data: Record&lt;string, unknown&gt;): any; setSlot(slotName: string, value: unknown): void; } &amp; IStateTreeNode&lt;...&gt;)[]</code></pre></dialog></span> |  | BaseSessionModel |
| <span id="getter-dialogcomponent">**DialogComponent**</span><br><code>DialogComponentType</code> |  | BaseSessionModel |
| <span id="getter-dialogprops">**DialogProps**</span><br><code>Record&lt;string, unknown&gt;</code> |  | BaseSessionModel |
| <span id="getter-animationmode">**animationMode**</span><br><code>AnimationMode</code> | resolved feature-layout animation mode (never undefined) | BaseSessionModel |
| <span id="getter-scrollzoom">**scrollZoom**</span><br><code>boolean</code> | resolved scroll-to-zoom preference. Global and personal (never shared in a session snapshot); every wheel-zoom view reads this single value. | BaseSessionModel |
| <span id="getter-numbergrouping">**numberGrouping**</span><br><code>boolean</code> | resolved thousand-separator preference. Read for display in the Preferences dialog; the formatter itself reads a plain module variable set at startup in each realm (see `setNumberGrouping`), because worker- built strings can't see a main-thread observable. | BaseSessionModel |
| <span id="getter-snackbarmessageset">**snackbarMessageSet**</span><br><code>Map&lt;string, SnackbarMessage&gt;</code> |  | [SnackbarModel](../snackbarmodel#getter-snackbarmessageset) |

## Methods

<!-- prettier-ignore -->
| Member | Description |
| --- | --- |
| <span id="method-getpreferencedefault">**getPreferenceDefault**</span><br><code>(key: string) =&gt; unknown</code> | the admin/embedder `configuration.preferences` value for a key, ignoring any runtime override — i.e. what a reset falls back to. Exposed rather than inlined because "differs from the default" is a question the Preferences reset diff asks about settings this map doesn't hold (see `defaultUseWorkspaces`). |
| <span id="method-getpreference">**getPreference**</span><br><code>(key: string) =&gt; unknown</code> | resolved value of a user preference: a runtime override if the user set one, otherwise the admin/embedder `configuration.preferences` default. The override map is empty unless the product loads it (web/desktop). |
| <span id="method-getdisplaytypedefault">**getDisplayTypeDefault**</span><br><code>(displayType: string, slot: string) =&gt; unknown</code> | resolved value of a per-display-type slot default the user promoted (see `setDisplayTypeDefault`); undefined when nothing was promoted. |
| <span id="method-getdisplaytypedefaults">**getDisplayTypeDefaults**</span><br><code>() =&gt; { displayType: string; slot: string; value: unknown; }[]</code> | every per-display-type default the user has promoted, as `{ displayType, slot, value }` — the inventory the Preferences dialog lists and clears one at a time (`setDisplayTypeDefault(…, undefined)`).<br><br>Here rather than filtered out of `getPreferenceChanges` by the dialog, because the composite-key layout is this file's: a consumer that recognized these rows by matching the path head is exactly the coupling `DISPLAY_TYPE_DEFAULTS_PATH_HEAD` stopped being exported over, where a rename on one side alone silently no-ops the other. |
| <span id="method-getpreferencechanges">**getPreferenceChanges**</span><br><code>() =&gt; TrackConfigChange[]</code> | every runtime preference-override that currently differs from its config/admin default, as `{ path, from, to }` rows — the exact set `clearPreferenceOverrides` reverts. Backs the confirmation diff shown before "Reset to defaults" (mirrors the per-track changes dialog). A scalar pref (animationMode, scrollZoom) whose override equals the default is omitted (reverting it is a no-op); each promoted per-display-type default is always a difference from the un-promoted state, so `from` reads "(default)". |

## Actions

<!-- prettier-ignore -->
| Member | Description | Defined by |
| --- | --- | --- |
| <span id="action-setselection">**setSelection**</span><br><code>(thing: unknown) =&gt; void</code> | set the global selection, i.e. the globally-selected object. can be a feature, a view, just about anything<br><br>A feature is unwrapped on the way in, so app state never holds a jexlFeatureProxy. `isFeature` accepts a proxy, but on one `id` is a data field rather than the method the Feature type promises — every consumer doing `isFeature(selection) ? selection.id() : …` would throw. | BaseSessionModel |
| <span id="action-clearselection">**clearSelection**</span><br><code>() =&gt; void</code> | clears the global selection | BaseSessionModel |
| <span id="action-sethovered">**setHovered**</span><br><code>(thing: unknown) =&gt; void</code> |  | BaseSessionModel |
| <span id="action-sethighlightsvisible">**setHighlightsVisible**</span><br><code>(arg: boolean) =&gt; void</code> | toggle all region highlight bands across every view | BaseSessionModel |
| <span id="action-revealhighlights">**revealHighlights**</span><br><code>() =&gt; void</code> | turn highlight bands back on, so a newly made highlight or bookmark is never silently swallowed by an earlier "highlights off" | BaseSessionModel |
| <span id="action-setpreferenceoverride">**setPreferenceOverride**</span><br><code>(key: string, value: unknown) =&gt; void</code> | set a runtime user-preference override (see `getPreference`). Mutates volatile state; products persist these to localStorage. An `undefined` value deletes the key (rather than leaving a phantom entry that `getPreference` reads as absent) so the store never holds dead keys. | BaseSessionModel |
| <span id="action-clearpreferenceoverrides">**clearPreferenceOverrides**</span><br><code>() =&gt; void</code> | clear every runtime preference override at once — scrollZoom, animationMode, and every promoted per-display-type default (see `setDisplayTypeDefault`) — so each falls back to its config/admin default. Backs the Preferences dialog "Reset to defaults" button. | BaseSessionModel |
| <span id="action-clearpreferenceoverride">**clearPreferenceOverride**</span><br><code>(key: string) =&gt; void</code> | clear a single runtime preference override (see `getPreference`) so it falls back to its config/admin default. Backs the per-entry reset in the Preferences dialog "Reset to defaults" confirmation. | BaseSessionModel |
| <span id="action-resetpreferencechange">**resetPreferenceChange**</span><br><code>(path: string[]) =&gt; void</code> | revert one row emitted by `getPreferenceChanges`, addressed by its display `path`. Backs the per-entry reset in the Preferences dialog's "Reset to defaults" confirmation.<br><br>Lives here rather than in that dialog because this model owns both path shapes it has to undo: a promoted per-display-type default, whose row path is a readable label over a flat composite storage key, and every other override, whose path *is* its key. The dialog used to re-derive the first case from an exported path-head constant. | BaseSessionModel |
| <span id="action-setscrollzoom">**setScrollZoom**</span><br><code>(flag: boolean) =&gt; void</code> | set the global scroll-to-zoom preference (see the `scrollZoom` getter) | BaseSessionModel |
| <span id="action-setdisplaytypedefault">**setDisplayTypeDefault**</span><br><code>(displayType: string, slot: string, value: unknown) =&gt; void</code> | promote (or, with `value` undefined, clear) a per-display-type slot default. Just a preference override under one flat composite key (see `displayTypeDefaultKey`), so it persists and independently tracks like any other pref, and clearing deletes only that key. | BaseSessionModel |
| <span id="action-setname">**setName**</span><br><code>(str: string) =&gt; void</code> |  | BaseSessionModel |
| <span id="action-setfocusedviewid">**setFocusedViewId**</span><br><code>(viewId: string &#124; undefined) =&gt; void</code> | `undefined` is "no view is focused", which the property has always been able to hold (`types.maybe`) and this had no way to spell. Nothing cleared it on teardown as a result: a view that was focused when it left the session left its id behind, and since every consumer compares `focusedViewId === view.id`, the id matched nothing, the focus ring vanished with nothing to say why, and the dead id persisted into a saved or shared session. `takeOut` clears it now. | BaseSessionModel |
| <span id="action-removeactivedialog">**removeActiveDialog**</span><br><code>() =&gt; void</code> |  | BaseSessionModel |
| <span id="action-queuedialog">**queueDialog**</span><br><code>(doneCallback: DoneCallback) =&gt; void</code> |  | BaseSessionModel |
| <span id="action-notify">**notify**</span><br><span class="cell-more"><button type="button" class="cell-more-trigger"><code>(message: string, level?: NotificationLevel &#124; undefined, action…</code></button><dialog class="cell-dialog"><form method="dialog"><button class="cell-dialog-close" aria-label="Close">✕</button></form><pre><code>(message: string, level?: NotificationLevel &#124; undefined, action?: SnackAction &#124; SnackAction[] &#124; undefined) =&gt; void</code></pre></dialog></span> |  | [SnackbarModel](../snackbarmodel#action-notify) |
| <span id="action-notifyerror">**notifyError**</span><br><span class="cell-more"><button type="button" class="cell-more-trigger"><code>(errorMessage: string, error?: unknown, extra?: unknown, action…</code></button><dialog class="cell-dialog"><form method="dialog"><button class="cell-dialog-close" aria-label="Close">✕</button></form><pre><code>(errorMessage: string, error?: unknown, extra?: unknown, action?: SnackAction &#124; undefined) =&gt; void</code></pre></dialog></span> |  | [SnackbarModel](../snackbarmodel#action-notifyerror) |
| <span id="action-seterrordialog">**setErrorDialog**</span><br><code>(state: ErrorDialogState &#124; undefined) =&gt; void</code> |  | [SnackbarModel](../snackbarmodel#action-seterrordialog) |
| <span id="action-pushsnackbarmessage">**pushSnackbarMessage**</span><br><span class="cell-more"><button type="button" class="cell-more-trigger"><code>(message: string, level?: NotificationLevel &#124; undefined, action…</code></button><dialog class="cell-dialog"><form method="dialog"><button class="cell-dialog-close" aria-label="Close">✕</button></form><pre><code>(message: string, level?: NotificationLevel &#124; undefined, actions?: SnackAction[] &#124; undefined) =&gt; void</code></pre></dialog></span> |  | [SnackbarModel](../snackbarmodel#action-pushsnackbarmessage) |
| <span id="action-popsnackbarmessage">**popSnackbarMessage**</span><br><code>() =&gt; SnackbarMessage &#124; undefined</code> |  | [SnackbarModel](../snackbarmodel#action-popsnackbarmessage) |
| <span id="action-removesnackbarmessage">**removeSnackbarMessage**</span><br><code>(message: string) =&gt; void</code> |  | [SnackbarModel](../snackbarmodel#action-removesnackbarmessage) |