[英]Angular: How to get value from an observable inside another observable
[英]How to use value from Observable inside TypeScript component | Angular 4
我试图获取从API获得的JSON值并将其设置在变量中,例如:
TS
this.graphicService.getDatas().subscribe(datas => {
this.datas = datas;
console.log(datas);
});
test = this.datas[0].subdimensions[0].entry;
的HTML
{{test}}
它在控制台上返回错误 :
ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'subdimensions' of undefined
TypeError: Cannot read property 'subdimensions' of undefined
at new GraphicsComponent (graphics.component.ts:33)...
但是,如果我像这样直接在HTML上使用,它确实可以工作 :
{{datas[0]?.subdimensions[0].entry}}
然后正确打印数据。 ..
尝试这个:
let test;
this.graphicService.getDatas().subscribe(datas => {
this.datas = datas;
console.log(datas);
test = this.datas[0].subdimensions[0].entry;
});
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