1// Copyright (C) 2020 The Android Open Source Project 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// Returns a wrapper around |f| which calls f at most once every |ms|ms. 16export function ratelimit(f: Function, ms: number): Function { 17 let inProgess = false; 18 return () => { 19 if (inProgess) { 20 return; 21 } 22 inProgess = true; 23 window.setTimeout(() => { 24 f(); 25 inProgess = false; 26 }, ms); 27 }; 28} 29 30// Returns a wrapper around |f| which waits for a |ms|ms pause in calls 31// before calling |f|. 32export function debounce(f: Function, ms: number): Function { 33 let timerId: undefined|number; 34 return () => { 35 if (timerId) { 36 window.clearTimeout(timerId); 37 } 38 timerId = window.setTimeout(() => { 39 f(); 40 timerId = undefined; 41 }, ms); 42 }; 43} 44