javascript 推送到 React 状态数组
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/52206812/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Pushing To React State Array
提问by user3637804
How can I write this better , I want to do it with setState instead of this.state.floors.push as I know that is bad practice but I couldnt figure it out. Im using react native.
我怎样才能写得更好，我想用 setState 而不是 this.state.floors.push 来做，因为我知道这是不好的做法，但我无法弄清楚。我正在使用本机反应。
FloorAPI.getFloorsByBuildingID(this.state.buildingID).then((response) => response.d.data.map((value) => {
console.log(value.floorName)
this.state.floors.push({value: value.floorName})
}))
回答by imjared
// Create a new array based on current state:
let floors = [...this.state.floors];
// Add item to it
floors.push({ value: floorName });
// Set state
this.setState({ floors });
回答by Hemadri Dasari
For now, the best possible and simplest way is
目前，最好和最简单的方法是
this.setState(previousState => ({
floors: [...previousState.floors, {"value": value.floorName}]
}));
回答by duxfox--
FloorAPI.getFloorsByBuildingID(this.state.buildingID).then((response) => {
// get current floors
const { floors } = this.state;
// get new floors after api request
const newfloors = response.d.data.map((value) => ({value: value.floorName}))
// set the new state by combining both arrays
this.setState({ floors: [...floors, ...newfloors] });
})
回答by Alauddin Afif Cassandra
const { floors } = this.state;
// Add item to it
floors.push({ value: 5 });
// Set state
this.setState({ floors });
回答by Aditya Kuppili
You can use
您可以使用
this.setState({floors: [{value: value.floorName}]});
in order to use set state.
为了使用设置状态。
回答by Bradey Whitlock
You can make a new variable and push to the variable then set the state after the map is complete
您可以创建一个新变量并推送到该变量然后在地图完成后设置状态
var tempArray = []
FloorAPI.getFloorsByBuildingID(this.state.buildingID).then((response) => response.d.data.map((value) => {
tempArray.push({value: value.floorName})
}))
this.setState({floors: tempArray})
回答by Dan Mehlqvist
You can always use the previous state.
您始终可以使用以前的状态。
setState((prevState)=>({
floors: prevState.floors.push({...})
});
Thats a nice way to avoid directly changing the state. Another way would be to do the following:
这是避免直接更改状态的好方法。另一种方法是执行以下操作：
var newState=[...this.state.floors];
newState.push({...});
setState(()=>({
floors: newState
)}
