How to add objects into objects dynamically in javascript?

Question

I am semi-new to javascript and would like to create something of this sort - a list of objects like this:

{ ID: 1, Field1: val1, Field2: val2, Field 3: val3 }

I know how to set this up if I create it statically but not sure how to handle it dynamically. In a given function, I will know the ID and one of the fields, but there are 3 separate functions to find each field/value so I need to update the objects with the fields/values as I learn them (hope this makes sense)

Can this be done and if so could someone help me with how or point me towards what I'm looking for? Thank you in advance for any help!

EDIT: I think my post was too vague, here is what I'd like to do:

When in function1, I will know the ID, let's say 1, & someField with a value of 'val' for example. So I will add this to an array.

In function2, I will know the ID, still 1, & differentField with a value of 2 for example. I want to access the object from before & add this new field/value to it (there will be more than one id/ object just using this as a base)

So in the array I want to be able to access the object by the ID & the known fields for that object

• Andrew Li: obj["Field" + num] = ....
• Andrew L: Read up on bracket notation for javascript property accessors developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…
• InsertDisplayName: @AndrewLi what is obj in this case? An object from within the list of objects? I'm trying to figure out how to create the list of objects dynamically and update the objects within that list/ add field/values as the code gets to them
• Bergi: Surely this can be done, but I don't have a clear idea of what you are trying to do. What do you mean by "there are 3 separate functions to find each field/value so I need to update the objects"? Can you post that code, please?
• InsertDisplayName: @Bergi sorry about that. I think my original post was too vague but I edited and added a scenario that I think helps explain what I want to do. Thanks!

Answer 1

Here is a small example that I think might help you. This creates objs with dynamic names and values and adds them to an array.

var myArray = [];
for (var i = 0; i < 3; i++) {
 var myObj = {};
 for (var x = 0; x < 3; x++) {
 myObj["Field" + x] = "val" + x;
 }
 myArray.push(myObj);
}
console.log(myArray)

Edit after Op's edit

Here is another example after your update. If I understood you then I think you really only need 1 function that is essentially an update to the array. Your JSON was a bit off too I think. In the example below The ID will reference an object that has a fields array where your "list" will be stored.

var myArray = [];
var testObj = {};
testObj.id = 1;
testObj.fields = [];
myArray.push(testObj)
// add myValue to the already existing obj with ID 1
addValue(1, "myValue");
// add myValue2 to the non-existent id 2 obj (it will be dynamically created)
addValue(2, "myValue2");
function addValue(id, val){
 var foundID = false;
 myArray.forEach(function(obj){
 if(obj.id === id){
 var newObj = {};
 newObj["Field" + id] = val;
 obj.fields.push(newObj);
 foundID = true;
 }
 });
 // if we did not find an obj with the passed in ID
 // then create and initialize it
 if(!foundID){
 var newIDObj = {};
 newIDObj.id = id;
 var fieldsArray = [];
 var newFieldsObj = {};
 newFieldsObj["Field" + id] = val;
 fieldsArray.push(newFieldsObj);
 newIDObj.fields = fieldsArray;
 myArray.push(newIDObj);
 }
}
console.log(myArray);
// How to access a value knowing the ID and the fieldName
var result = getValue(1, "Field1");
// If no result is found, undefined will be returned
// This assumes Field Names are all unique!
function getValue(id, fieldName) {
 var result;
 myArray.forEach(function(currentObj) {
 if (currentObj.id === id) {
 currentObj.fields.forEach(function(currentField) {
 if (typeof currentField[fieldName] !== "undefined") {
 result = currentField[fieldName];
 }
 });
 }
 });
 
 console.log("The value with ID: " + id + " and field name: " + fieldName + " is: " + result)
 return result;
}

• InsertDisplayName: Thanks! This & the link are helpful but I still have some questions. I might have been too vague in my post. What I'd like to do: When in function1, I will know the ID, let's say 1, & someField with a value of 'val' for example. So I will add this to an array In function2, I will know the ID, still 1, & differentField with a value of 2 for example. I want to access the object from before & add this new field/value to it (there will be more than one id/ object just using this as a base) So in the array I want to be able to access the object by the ID & the known fields for that object
• Andrew L: I added another example, not 100% on your wording, but maybe it will help you
• InsertDisplayName: with this solution is there a way for me to get the value of a field (one of the objects in the field array) knowing the ID and the field name?
• Andrew L: I updated the answer with a function that can find you the fieldName value knowing the ID and field name.