我在如何在我的卡片上显示每个主题的数据方面遇到了问题。
HTML
<ion-item *ngFor="let topic of topicCluster" (click)="viewTopic(topic.slug)">
<strong>{{topic?.number}}. {{topic?.name}}</strong>
</ion-item>TS
this.topicProvider.getClusters().subscribe(cluster => {
this.clusters = cluster
console.log(this.clusters)
cluster.forEach(element => {
const topicArr = []
for (var key in element.topics){
this.topicProvider.getTopic(key).subscribe(topic => {
topicArr.push(topic)
})
}
this.topicCluster = topicArr
console.log(this.topicCluster)
})
})问题：
1st Card:
14th Topic
15th Topic
..
5th Card:
14th Topic
15th Topic应该是：
1st Card:
14th Topic
15th Topic
..
5th Card:
14th Topic
15th Topic这是我拥有的数据
回答 1
Stack Overflow用户
发布于 2018-01-22 07:42:29
需要更新您的for循环，因为有一个异步订阅调用，它将丢失上下文。for循环将循环，并将键的最后一个值传递给异步。您可以使用IIFE来避免这种情况。
let self = this;
self.topicProvider.getClusters().subscribe(cluster => {
self.clusters = cluster
console.log(self.clusters);
cluster.forEach(element => {
const topicArr = []
for (var key in element.topics){
(function(keyData){
self.topicProvider.getTopic(keyData).subscribe(topic => {
topicArr.push(topic);
})
})(key);
}
self.topicCluster = topicArr
console.log(self.topicCluster)
})
})页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/48375978
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