1

I have a class definition…

class anObj { 
  "ID" : string;
  dialog: {[id : number]:{hide: boolean;}} = {
    0 : {"hide": false},
    14 : {"hide": false}
  }    
}
class manyObjects {
  myGroup: anObj [] = [];
}
...
public stuff = manyObjects;

This totally works just the way I'd like for it to...I can use the id value as a direct key...

var x:number = 1 //used for a different tier of logic
stuff.myGroup[x].dialog[14].hide!=true

Here's where I'm stuck... I'd like to add more dialogs to the group. I get all the way our to...

stuff.myGroup[x].dialog

and can't figure out how to add something like with a push...

.push(7 : {"hide": true})

for example, I can type this line and the IDE says it's ok... 

stuff.myGroup[x].dialog[[id=7].push({"hide": false})];

however, when I check, the element does not get added to the array...

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4
  • .push() modifies the original array, and doesn't return the new array. Commented Jan 14, 2020 at 6:59
  • yes, Sunny Patel, I want to add a new item to the existing array. I'm not attempting to return it yet. How would you add a new item to it? say one that looks like this... 7 : {"hide": true} Commented Jan 14, 2020 at 7:31
  • I'm not adding a new dialog. I'm building what I now call an asymmetrical key/value pair index array, eg myThing: {[myKey: type] :{key1: type; key2: type}} = {"salutation" : {"key1": "Hi"}, {"key2": "How are you?"}, "conversation" : {"key1": "'s good"}, {"key2": "How about dem Mets?"}} This works if you fully declare ALL elements, eg myThing[salutation].key2 == "How are you?". Makes it REALLY easy to find a specific value without looping all keys by an index. However! I want to add a new element, like "departure" : {"key1": "It's been good."}, {"key2": "see ya!"} and can't. Commented Jan 14, 2020 at 15:54
  • There is no JSON here. JSON is a text format for moving and storing data. See There is no such thing as a JSON Object. Commented Jan 14, 2020 at 16:29

1 Answer 1

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1

What I could gather from your code is that you're trying to add a new dialog to the object contained in the "dialog" property of anObj, which is not an array. It's an object with an expected structure in typescript: every property of that object should be a number, and the value of every property should be of type {hide: boolean;}.

From there, it's quite easy, you add a new property (or overwrite an existing one) as you do for any JS object:

stuff.myGroup[x].dialog[7] = {hide: false};

Again, stuff.myGroup[x].dialog is an object, not an array, the array is stuff.myGroup. If you want to add another "group" to myGroup then you'd do something like:

stuff.myGroup.push(new anObj());

EDIT

Example that ignores the noise created by extra objects like stuff and my group, but demonstrates adding a new key-value pair:

class anObj { 
  "ID" : string;
  dialog: {[id : number]:{hide: boolean;}} = {
    0 : {"hide": false},
    14 : {"hide": false}
  }    
}
class manyObjects {
  myGroup: anObj [] = [];
}

var obj = new anObj();
obj.dialog[7] = { hide: true };
console.log(obj);

You can try that in typescript playground -> https://www.typescriptlang.org/play/?ssl=14&ssc=18&pln=1&pc=1#code/MYGwhgzhAEYHYHkBGAraBvaAoa0BEAkgCJ7QBc0EALgE4CWcA5gNw7QAmdYIA9oxegDadduWhwArgFskAUxoBdMugAWI2RSQ8eIWfGYBfA9AC8GNrgAMY9HjXtZeCgDNuEWQYA0F6AEYALDZ26k7QriDuBmzGuNhRoJAwUvAAnsgossBUMOhsUikA4jQ8EgAOFPDp0IIKptUKrFFYAG5gNNA8qHVwsgDusIioABQAlKydKAB0nNx8ggDstWaY9hrQtBKy0AaswDxwEDqyk7yMQxNjQA

Update 2

To return the enumerable keys of an object, you can use the Object.keys method. See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys

console.log(Object.Keys(obj));
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5 Comments

I'm not adding a new dialog. I'm building what I now call an asymmetrical key/value pair index array, eg myThing: {[myKey: type] :{key1: type; key2: type}} = {"salutation" : {"key1": "Hi"}, {"key2": "How are you?"}, "conversation" : {"key1": "'s good"}, {"key2": "How about dem Mets?"}} This works if you fully declare ALL elements, eg myThing[salutation].key2 == "How are you?". Makes it REALLY easy to find a specific value without looping all keys by an index. However! I want to add a new element, like "departure" : {"key1": "It's been good."}, {"key2": "see ya!"} and can't.
You can call it whatever you want, in javascript that's going to still be a plain object. Now the question is what's preventing you from adding a new key value pair: a typescript compilation error, or a runtime error? Something else? And I have to repeat that you need to take care where and how you add it. The first example I've posted covers the key-value pair, where key is 7 and value is the object {hide: false}
Very cool! I get it. So... if I understand you correctly... if I declare in this way... keyName: {[id : (number or string)] : {key1: type; key2: type}}; in order to add any new element, I don't use push() at all, instead I just treat the new element as if it already exists, and set the value like this... dialog[7] = { hide: true, other: 6} … and then in the future instead of looping through keys looking for 7, I can just directly reference it, var i = 7; if(dialog[i]!=undefined) { //do something with dialog[7].hide} …like that saves around 30 lines of code and a ton of potential bugs! THANKS!
Quick follow-up question... how can you determine the count of dialogs declared for the obj or iterate through them if it's not an array?
Updated with the answer to your follow-up question.

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