1// Copyright (C) 2023 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 15import m from 'mithril'; 16 17// Check if a mithril component vnode has children 18export function hasChildren<T>({children}: m.Vnode<T>): boolean { 19 return ( 20 Array.isArray(children) && 21 children.length > 0 && 22 children.some((value) => value) 23 ); 24} 25 26// A component which simply passes through it's children. 27// Can be used for having something to attach lifecycle hooks to without having 28// to add an extra HTML element to the DOM. 29export const Passthrough = { 30 view({children}: m.VnodeDOM) { 31 return children; 32 }, 33}; 34 35export interface GateAttrs { 36 open: boolean; 37} 38 39// The gate component is a wrapper which can either be open or closed. 40// - When open, children are rendered inside a div where display = contents. 41// - When closed, children are rendered inside a div where display = none 42// Use this component when we want to conditionally render certain children, 43// but we want to maintain their state. 44export const Gate = { 45 view({attrs, children}: m.VnodeDOM<GateAttrs>) { 46 return m( 47 '', 48 { 49 style: {display: attrs.open ? 'contents' : 'none'}, 50 }, 51 children, 52 ); 53 }, 54}; 55