1 /* 2 * Copyright (C) 2022 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.settingslib.spa.framework.util 18 19 import kotlinx.coroutines.flow.Flow 20 import kotlinx.coroutines.flow.combine 21 import kotlinx.coroutines.flow.map 22 import kotlinx.coroutines.flow.take 23 24 /** 25 * Returns a [Flow] whose values are a list which containing the results of applying the given 26 * [transform] function to each element in the original flow's list. 27 */ 28 inline fun <T, R> Flow<List<T>>.mapItem(crossinline transform: (T) -> R): Flow<List<R>> = 29 map { list -> list.map(transform) } 30 31 /** 32 * Returns a [Flow] whose values are a list which containing the results of asynchronously applying 33 * the given [transform] function to each element in the original flow's list. 34 */ 35 inline fun <T, R> Flow<List<T>>.asyncMapItem(crossinline transform: (T) -> R): Flow<List<R>> = 36 map { list -> list.asyncMap(transform) } 37 38 /** 39 * Returns a [Flow] whose values are a list containing only elements matching the given [predicate]. 40 */ 41 inline fun <T> Flow<List<T>>.filterItem(crossinline predicate: (T) -> Boolean): Flow<List<T>> = 42 map { list -> list.filter(predicate) } 43 44 /** 45 * Delays the flow a little bit, wait the other flow's first value. 46 */ 47 fun <T1, T2> Flow<T1>.waitFirst(otherFlow: Flow<T2>): Flow<T1> = 48 combine(otherFlow.take(1)) { value, _ -> value } 49