docs(ThrottleConfig): document "leading" and "trailing" behaviour

src/internal/operators/throttle.ts

@@ -5,8 +5,33 @@ import { operate } from '../util/lift';
 import { createOperatorSubscriber } from './OperatorSubscriber';
 import { innerFrom } from '../observable/innerFrom';
 
+/**
+ * An object interface used by {@link throttle} or {@link throttleTime} that ensure
+ * configuration options of these operators.
+ *
+ * @see {@link throttle}
+ * @see {@link throttleTime}
+ */
 export interface ThrottleConfig {
+  /**
+   * If `true`, the resulting Observable will emit the first value from the source
+   * Observable at the **start** of the "throttling" process (when starting an
+   * internal timer that prevents other emissions from the source to pass through).
+   * If `false`, it will not emit the first value from the source Observable at the
+   * start of the "throttling" process.
+   *
+   * If not provided, defaults to: `true`.
+   */
   leading?: boolean;
+  /**
+   * If `true`, the resulting Observable will emit the last value from the source
+   * Observable at the **end** of the "throttling" process (when ending an internal
+   * timer that prevents other emissions from the source to pass through).
+   * If `false`, it will not emit the last value from the source Observable at the
+   * end of the "throttling" process.
+   *
+   * If not provided, defaults to: `false`.
+   */
   trailing?: boolean;
 }
 
@@ -48,11 +73,11 @@ export interface ThrottleConfig {
  * @see {@link sample}
  * @see {@link throttleTime}
  *
- * @param durationSelector A function
- * that receives a value from the source Observable, for computing the silencing
- * duration for each source value, returned as an Observable or a Promise.
- * @param config a configuration object to define `leading` and `trailing` behavior. Defaults
- * to `{ leading: true, trailing: false }`.
+ * @param durationSelector A function that receives a value from the source
+ * Observable, for computing the silencing duration for each source value,
+ * returned as an `ObservableInput`.
+ * @param config A configuration object to define `leading` and `trailing`
+ * behavior. Defaults to `{ leading: true, trailing: false }`.
  * @return A function that returns an Observable that performs the throttle
  * operation to limit the rate of emissions from the source.
  */

src/internal/operators/throttleTime.ts

@@ -47,7 +47,7 @@ import { timer } from '../observable/timer';
  * internally by the optional `scheduler`.
  * @param scheduler The {@link SchedulerLike} to use for
  * managing the timers that handle the throttling. Defaults to {@link asyncScheduler}.
- * @param config a configuration object to define `leading` and
+ * @param config A configuration object to define `leading` and
  * `trailing` behavior. Defaults to `{ leading: true, trailing: false }`.
  * @return A function that returns an Observable that performs the throttle
  * operation to limit the rate of emissions from the source.