Arrays 如何显示JSON数组的一部分?
我怎么能只展示这部分 /db/User_DataDb/61500546-4e63-42fd-9d54-b92d0f7b9be1 对象对象选择: 我写Arrays 如何显示JSON数组的一部分?,arrays,object,typescript,Arrays,Object,Typescript,我怎么能只展示这部分 /db/User_DataDb/61500546-4e63-42fd-9d54-b92d0f7b9be1 对象对象选择: 我写 console.log("obj.sel_an: ", JSON.stringify(this.sel_and.__zone_symbol__value)) 控制台显示此错误:“obj.sel\u an:未定义。” @米萨兹这是我在上一次评论中提到的答案 这是我的代码的一部分 db.Coll1.find() .equal('i
console.log("obj.sel_an: ",
JSON.stringify(this.sel_and.__zone_symbol__value))
控制台显示此错误:“obj.sel\u an:未定义。”
@米萨兹这是我在上一次评论中提到的答案
这是我的代码的一部分
db.Coll1.find()
.equal('id', and.id)
.resultList(result => {
result.forEach(db1 => {
if (db1.sel_and === null) {
db1.sel_and = new Set();
}
if (db1.sel_an === null) {
db1.sel_an = new Array();
}
db1.sel_an.push(promise1); // here is a JsonArray
db1.sel_and.add(promise1); // here is a Set()
var db_child: any;
db_child = db1.sel_and.forEach(function (child) {console.log(child[0].__zone_symbol__value) });
console.log(" db1.sel_and: ", db_child);
return db1.update({ refresh: true });
});
以下是JsonArray的结果
保存在集合中 [ { “\uuuu区域\uu符号\uuuuu状态”:真, “\uuuuu区域\u符号\uuuuuu值”:“/db/User\u DataDb/f6fe3fe3-17f1-49d8-83c3-b36dda42026d” } ]
ZoneAwarePromise {__zone_symbol__state: null, __zone_symbol__value: Array(0)}
__zone_symbol__state:true
__zone_symbol__value:"/db/User_DataDb/d79ef084-17fc-441c-a8eb-13ba0a14f083"
__proto__:Object
Uncaught (in promise): TypeError: Cannot read property '__zone_symbol__value' of undefined
TypeError: Cannot read property '__zone_symbol__value' of undefined
at http://localhost:3000/main.bundle.js:28348:116
at Set.forEach (native)
at http://localhost:3000/main.bundle.js:28348:69
at Array.forEach (native)
at http://localhost:3000/main.bundle.js:28336:44
at ZoneDelegate.invoke (http://localhost:3000/polyfills.dll.js:4341:26)
at Object.onInvoke (http://localhost:3000/vendor.dll.js:30326:37)
at ZoneDelegate.invoke (http://localhost:3000/polyfills.dll.js:4340:32)
at Zone.run (http://localhost:3000/polyfills.dll.js:4133:43)
at http://localhost:3000/polyfills.dll.js:4720:57
at ZoneDelegate.invokeTask (http://localhost:3000/polyfills.dll.js:4374:31)
at Object.onInvokeTask (http://localhost:3000/vendor.dll.js:30317:37)
at ZoneDelegate.invokeTask (http://localhost:3000/polyfills.dll.js:4373:36)
at Zone.runTask (http://localhost:3000/polyfills.dll.js:4173:47)
at drainMicroTaskQueue (http://localhost:3000/polyfills.dll.js:4553:35)
at ZoneTask.invoke (http://localhost:3000/polyfills.dll.js:4431:25)
如果我不在child的末尾写入[0],我将得到“未定义”。如果我写入child.\uuuu zone\u symbol\uu值,我将出错。我怎么能
省去“[0]。\u区域\u符号\u值”而不出现错误?是
有可能吗
谢谢
这个.sel\u和[0]。\uuu区域\u符号\uu值
@dbandstra你好,谢谢,它正在工作。如果我知道对象的确切索引,它就起作用了。如果对象具有更多信息并且位于数据库集合中,我希望复制该信息并将其保存在另一个数据库集合中。然后我想用Angular2同时显示两个集合的保存数据。你知道我怎么做吗?我试图将这个对象以Set()和Array()的形式保存到数据库中,并用html显示它。但它不起作用。或者我应该试着问论坛吗?使用for
循环或forEach函数,该函数在this.sel_和
obejct上可用。例如:this.sel_和.forEach(函数(子){console.log(子.\uuu区域\u符号\uu值)})代码>@Misaz,你好,谢谢。我将用另一个评论来回答你。
Set(1) {ZoneAwarePromise {__zone_symbol__state: true, __zone_symbol__value: "/db/User_DataDb/f55bf96d-2cb9-467f-8aa8-d60aced32fcf"}}
size:(...)
__persistedSize__:1
__persistedState__:Object
__proto__:Set
[[Entries]]:Array(1)
0:null
length:1
3.
db_child = db1.sel_and.forEach(function (child) { console.log(child[0].__zone_symbol__value) });
console.log(" db1.sel_and: ", db_child);
Uncaught (in promise): TypeError: Cannot read property '__zone_symbol__value' of undefined
TypeError: Cannot read property '__zone_symbol__value' of undefined
at http://localhost:3000/main.bundle.js:28348:116
at Set.forEach (native)
at http://localhost:3000/main.bundle.js:28348:69
at Array.forEach (native)
at http://localhost:3000/main.bundle.js:28336:44
at ZoneDelegate.invoke (http://localhost:3000/polyfills.dll.js:4341:26)
at Object.onInvoke (http://localhost:3000/vendor.dll.js:30326:37)
at ZoneDelegate.invoke (http://localhost:3000/polyfills.dll.js:4340:32)
at Zone.run (http://localhost:3000/polyfills.dll.js:4133:43)
at http://localhost:3000/polyfills.dll.js:4720:57
at ZoneDelegate.invokeTask (http://localhost:3000/polyfills.dll.js:4374:31)
at Object.onInvokeTask (http://localhost:3000/vendor.dll.js:30317:37)
at ZoneDelegate.invokeTask (http://localhost:3000/polyfills.dll.js:4373:36)
at Zone.runTask (http://localhost:3000/polyfills.dll.js:4173:47)
at drainMicroTaskQueue (http://localhost:3000/polyfills.dll.js:4553:35)
at ZoneTask.invoke (http://localhost:3000/polyfills.dll.js:4431:25)