diff --git a/src/selection.ts b/src/selection.ts
index 137fb67798..e607590b7c 100644
--- a/src/selection.ts
+++ b/src/selection.ts
@@ -220,10 +220,10 @@ export interface SelectionParameter<T extends SelectionType = SelectionType> {
    * __See also:__ [`init`](https://vega.github.io/vega-lite/docs/value.html) documentation.
    */
   value?: T extends 'point'
-  ? SelectionInit | SelectionInitMapping[]
-  : T extends 'interval'
-  ? SelectionInitIntervalMapping
-  : never;
+    ? SelectionInit | SelectionInitMapping[]
+    : T extends 'interval'
+    ? SelectionInitIntervalMapping
+    : never;
 
   /**
    * When set, a selection is populated by input elements (also known as dynamic query widgets)
@@ -238,10 +238,10 @@ export interface SelectionParameter<T extends SelectionType = SelectionType> {
    * __See also:__ [`bind`](https://vega.github.io/vega-lite/docs/bind.html) documentation.
    */
   bind?: T extends 'point'
-  ? Binding | Record<string, Binding> | LegendBinding
-  : T extends 'interval'
-  ? 'scales'
-  : never;
+    ? Binding | Record<string, Binding> | LegendBinding
+    : T extends 'interval'
+    ? 'scales'
+    : never;
 }
 
 export type TopLevelSelectionParameter = SelectionParameter & {
@@ -254,29 +254,29 @@ export type TopLevelSelectionParameter = SelectionParameter & {
 
 export type ParameterExtent =
   | {
-    /**
-     * The name of a parameter.
-     */
-    param: ParameterName;
-
-    /**
-     * If a selection parameter is specified, the field name to extract selected values for
-     * when the selection is [projected](https://vega.github.io/vega-lite/docs/selection.html#project) over multiple fields or encodings.
-     */
-    field?: FieldName;
-  }
+      /**
+       * The name of a parameter.
+       */
+      param: ParameterName;
+
+      /**
+       * If a selection parameter is specified, the field name to extract selected values for
+       * when the selection is [projected](https://vega.github.io/vega-lite/docs/selection.html#project) over multiple fields or encodings.
+       */
+      field?: FieldName;
+    }
   | {
-    /**
-     * The name of a parameter.
-     */
-    param: ParameterName;
-
-    /**
-     * If a selection parameter is specified, the encoding channel to extract selected values for
-     * when a selection is [projected](https://vega.github.io/vega-lite/docs/selection.html#project) over multiple fields or encodings.
-     */
-    encoding?: SingleDefUnitChannel;
-  };
+      /**
+       * The name of a parameter.
+       */
+      param: ParameterName;
+
+      /**
+       * If a selection parameter is specified, the encoding channel to extract selected values for
+       * when a selection is [projected](https://vega.github.io/vega-lite/docs/selection.html#project) over multiple fields or encodings.
+       */
+      encoding?: SingleDefUnitChannel;
+    };
 
 export type PointSelectionConfigWithoutType = Omit<PointSelectionConfig, 'type'>;