将新对象添加到现有对象。 Javascript

Question

I have read SO and others but more complex For referrence:

let newpage = {
  page_no_3: {
    data1: [{index: 1, text: "test1"}],
    data2: [{index: 1, text: "test2"}],
  }
}

What I want to happen when I add new object:

let newpage = {
  page_no_3: {
    data1: [{index: 1, text: "test2"}, {index: 2, text: "test3"}, ...]
    data2: [{index: 1, text: "test2"}, {index: 2, text: "test4"}, ...]
  }
}

NOTE: Sorry it should not be an array but an object.

NOTE2: Sorry again. it should be Array with objects as elements.

PS: When I try to get the data of data1 before inserting, it is giving me an undefined error. I tried it like this:

let page_no = 'page_no_3'
if (nextpage.length == 0) {
    ///
} else { // Both undefined
    console.log(nextpage[page_no].data1)
    console.log(nextpage["page_no_3"].data1)
}

But if I only console.log(nextpage[page_no]) I can see the {index: 1, text: "test2"}.

Answer 1

First check that your array exist :

if(newpage["page_no_3"].data1 === undefined){
   newpage["page_no_3"].data1 = [];
}

Then you can add a new object to data1 :

newpage["page_no_3"].data1.push(myAwesomeObject);

maybe this can help you to understand the difference between arrays and objects