我不太熟悉Angular 观测.我有一个问题,我想在subscribe方法中返回一个值.我有
getTotalQuestions(idForm:string){
let totalQuestions:number;
this.getFirebaseData(idForm+"/Metadatos")
.subscribe(items =>
{
items.map(item => {
totalQuestions=item.Total;
console.log(totalQuestions);
});
}
);
console.log(totalQuestions);
return totalQuestions;
}
前console.log(totalQuestions)
张打印4张,后console.log(totalQuestions)
张打印undefined张.
getTotalQuestions(idForm:string){
let totalQuestions:number;
this.getFirebaseData(idForm+"/Metadatos")
.subscribe(items =>
{
items.map(item => {
totalQuestions=item.Total;
console.log(totalQuestions);
});
}
);
console.log(totalQuestions);
return totalQuestions;
}
第一个console.log(totalQuestions)
不打印任何内容,第二个console.log(totalQuestions)
打印未定义的内容.我不明白为什么会这样.
我希望你能帮我澄清我不理解的概念.谢谢