Searching for values using keys in Angular

Question

Searching for values using keys in Angular

Currently, I am working on a project using Angular where I need to store information based on specific identifiers. To display this information in the Angular application, I am pulling data for different identifiers and showing it on the screen.

At the moment, my approach is as follows:

var arrayInfo = [[]];

var data = {
    id: 950252,
    text: "Hello world."
};

arrayInfo[data.id] = data;

This method allows me to access the information in AngularHTML like this:

{{arrayInfo[id].text}} // Hello world.

However, one major drawback of this method is that the array ends up with a large number of null values due to having indices up to X (where X is the highest identifier). For instance, in this scenario alone, there are 950,252 array elements stored as "null". This method doesn't seem very efficient.

Another solution I'm considering involves storing the data differently:

var dataArray = [];

var newData = {
    id: 950252,
    text: "Hello world."
};

dataArray.push(newData);

But the challenge with this approach is that I won't know the exact index where the data with an id of 950252 is stored because it will be at a random position in the array (based on when it was inserted using push). As a result, I won't be able to directly access it using dataArray[id].

javascript arrays angularjs

Answer 1

Answer №1

A more efficient way to store data is by using object literals instead of arrays. When using an array, there is a risk of creating sparse arrays with gaps. By using an object literal, you can treat the id as a key rather than an index, making lookup easier and more straightforward.

For example:

Replace

var list = [];

with

var list = {};
//....
list[item.id] = item;

If you still want to keep an array of objects and also maintain a hash, you can create another variable to hold it or add a property directly on the array object itself like this:

var list = [];
list.hash = {};
//
list.hash[item.id] = (list.push(item) - 1);
// To retrieve the value based on id:
var selectedItem = list[list.hash[id]];

Note: Make sure to properly manage and update the hash indices if you are adding or removing items from the array. Also, consider how you associate this object with the scope or controller instance for binding purposes.

Answer 2

A more efficient way to store data is by using object literals instead of arrays. When using an array, there is a risk of creating sparse arrays with gaps. By using an object literal, you can treat the id as a key rather than an index, making lookup easier and more straightforward.

For example:

Replace

var list = [];

with

var list = {};
//....
list[item.id] = item;

If you still want to keep an array of objects and also maintain a hash, you can create another variable to hold it or add a property directly on the array object itself like this:

var list = [];
list.hash = {};
//
list.hash[item.id] = (list.push(item) - 1);
// To retrieve the value based on id:
var selectedItem = list[list.hash[id]];

Note: Make sure to properly manage and update the hash indices if you are adding or removing items from the array. Also, consider how you associate this object with the scope or controller instance for binding purposes.

Searching for values using keys in Angular

Answer №1

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