Configuration defaults

Every plugin declares a default for each plugin_config and columns_config key it understands. Two static methods on the <perspective-viewer> element class replace those defaults for every viewer on the page:

const Viewer = customElements.get("perspective-viewer");

// Every plugin that declares `group_pad` now defaults it to 10.
Viewer.setPluginConfigDefaults({ group_pad: 10 });

// Datetime columns render in UTC in every plugin.
Viewer.setColumnConfigDefaults(
    { date_format: { timeZone: "UTC" } },
    { type: "datetime" },
);

A replaced default behaves exactly like the plugin’s own:

• The settings and column style editors show it as the unedited value.
• A value equal to it is left out of save(), saveWorkspace() and the perspective-config-update event, so a column nobody edited saves nothing.
• The plugin renders it wherever the stored config leaves the key out.
• restore() drops a value equal to it, like any other default.

Defaults are part of the host application, like registered plugins and themes. They are never saved, and restore() and reset() never change them.

Narrowing

Both methods take an options object:

Without plugin, a default applies to every plugin that declares the key and is ignored by the rest. When several defaults set the same key, the most specific wins:

plugin_config defaults follow the same order without the type levels.

Merging and removing

Each call merges into the defaults set by earlier calls with the same options. null removes a default at any depth:

getPluginConfigDefaults() and getColumnConfigDefaults() return the current defaults, one entry per combination of options.

Formats

date_format and number_format defaults combine with the plugin’s declared format and with a column’s stored format by group rather than as a whole:

So a page-wide timeZone reaches a column whose user picked a long date, while a default dateStyle never mixes with a column’s own per-part fields. A number_format default that sets one digit bound inherits the other from the plugin, so { maximumFractionDigits: 4 } on a datagrid float column means 2 to 4 digits.

In the charts, a date_format default that sets only timeZone or hour12 keeps the adaptive axis labels, which choose their precision from the zoom level. A default that sets a display field, or any number_format default, fixes that type’s axis labels to the format, as a format chosen in the column style editor does.

Setting defaults before restoring

Call these methods before load() and restore(). restore() drops values equal to the defaults in force at that moment, so a config restored first loses any value equal to the plugin’s own default, and a default set afterwards then replaces it.

Saved configs leave out values equal to the defaults. Restoring one in an application without the same defaults renders the plugins’ own defaults instead.

A default for a key whose plugin default comes from the column’s data, such as a gradient’s maximum, replaces that computed value with the fixed one.

Errors

A call throws when its arguments are malformed: defaults is not an object or null, plugin names no registered plugin, type is not a column type, or a date_format mixes dateStyle/timeStyle with per-part fields. A value that a particular plugin cannot use, such as an Enum value outside its choices or a number outside its range, is logged as an error naming the plugin, column and key, and that plugin keeps its own default.