Javascript 可能未处理的承诺拒绝 (id:0) 警告
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/47936361/
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
提示：将鼠标放在中文语句上可以显示对应的英文。显示中英文
时间：2020-08-23 03:59:10 来源:igfitidea点击:
Possible Unhandled Promise Rejection (id:0) Warning
提问by I'm not human
I am getting the following warning message when my AsyncStorage Item is empty "Possible Unhandled Promise Rejection (id:0)"So my question is: How can I handle a promise rejection?
当我的 AsyncStorage 项为空“可能未处理的承诺拒绝（id：0）”时，我收到以下警告消息所以我的问题是：如何处理承诺拒绝？
My code:
我的代码：
componentDidMount() {
try {
// This warning only appears when 'connections' item is empty
AsyncStorage.getItem('connections').then((token) => {
token = JSON.parse(token);
const getSectionData = (dataBlob, sectionId) => dataBlob[sectionId];
const getRowData = (dataBlob, sectionId, rowId) => dataBlob[`${rowId}`];
const ds = new ListView.DataSource({
rowHasChanged: (r1, r2) => r1 !== r2,
sectionHeaderHasChanged: (s1, s2) => s1 !== s2,
getSectionData,
getRowData,
});
const {dataBlob, sectionIds, rowIds} = this.formatData(token);
this.setState({
dataSource: ds.cloneWithRowsAndSections(dataBlob, sectionIds, rowIds),
});
});
}catch(error) {
console.log(error);
}
}
回答by HMR
You need to catch the reject of the promise:
你需要抓住承诺的拒绝：
componentDidMount() {
// This warning only appears when 'connections' item is empty
return AsyncStorage.getItem('connections').then((token) => {
token = JSON.parse(token);
const getSectionData = (dataBlob, sectionId) => dataBlob[sectionId];
const getRowData = (dataBlob, sectionId, rowId) => dataBlob[`${rowId}`];
const ds = new ListView.DataSource({
rowHasChanged: (r1, r2) => r1 !== r2,
sectionHeaderHasChanged: (s1, s2) => s1 !== s2,
getSectionData,
getRowData,
});
const { dataBlob, sectionIds, rowIds } = this.formatData(token);
this.setState({
dataSource: ds.cloneWithRowsAndSections(dataBlob, sectionIds, rowIds),
});
}).catch(error => {
console.log(error);
})
}
