我对以下选择器有疑问:
export const selectInfoFromMap = createSelector(featureSelector, (state, props) =>
state.attributes.get(props.userName).get(props.parameterUser).userValue);
在组件初始化期间,下面的 map 不存在。我可以轻松检查空值。
export const selectInfoFromMap = createSelector(featureSelector, (state, props) =>
state.attributes.get(props.userName).get(props.parameterUser).userValue ?
state.attributes.get(props.userName).get(props.parameterUser).userValue : '0.0');
但是,是否可以检查 undefined?
最佳答案
这是对属性的深入挖掘,你最好使用 try catch
export const selectInfoFromMap = createSelector(featureSelector, (state, props) =>{
try{
return state.attributes.get(props.userName).get(props.parameterUser).userValue
}catch(e){
return '0.0'
}
关于angular - NGRX 8, Angular ,如何处理未定义的错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57878299/