queryTextChanges.kt

/**
 * Return query text changes observable.
 *
 * - filter: to filter undesired text like blank text to avoid unnecessary API call.
 * - debounce: to ignore the previous items in the given time and only emit the last one, to avoid too much API calls.
 * - distinctUntilChanged: to avoid the duplicate API call.
 */
fun EditText.queryTextChanges(): Observable<String> {
    return textChanges()
            .map { it.toString() }
            .filter { it.isNotBlank() }
            .debounce(300, TimeUnit.MILLISECONDS)
            .distinctUntilChanged()
}