Store a distinct identifier as an object within a JavaScript collection

Question

Store a distinct identifier as an object within a JavaScript collection

I am attempting to save a key as an object in JavaScript by using the Map collection:


let tempEntry = {y:y, x:x}
let exist = map1.has(tempEntry);

if(exist){
    map1.set(tempEntry, true)
} else {
    map1.set(tempEntry, false)
}

However, I am facing an issue where it cannot find the key and always returns exist as false. I have a list where I also take the x and y values and put them in the tempEntry variable.

What I aim to accomplish is to create a list of objects with the format key: {y:y, x:x}, value: true/false.

Does anyone have an alternate method to achieve this?

javascript

Answer 1

Answer №1

Map#has function checks if the object reference is the same.

If there is another object with the same keys and values, it will not be considered the original object.

var x = 4,
    y = 4,
    tempEntry = { y, x },
    map1 = new Map;

map1.set(tempEntry, map1.has(tempEntry));
console.log([...map1]);

map1.set(tempEntry, map1.has(tempEntry)); // returns true
console.log([...map1]);

tempEntry = { y, x };

map1.set(tempEntry, map1.has(tempEntry)); // a new object
console.log([...map1]);

.as-console-wrapper { max-height: 100% !important; top: 0; }

A possible solution could involve serializing the object into a string, as long as the order of the keys remains the same.

var x = 4,
    y = 4,
    tempEntry = JSON.stringify({ y, x }),
    map1 = new Map;

map1.set(tempEntry, map1.has(tempEntry));
console.log([...map1]);

tempEntry = JSON.stringify({ y, x });

map1.set(tempEntry, map1.has(tempEntry)); // same object
console.log([...map1]);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

Map#has function checks if the object reference is the same.

If there is another object with the same keys and values, it will not be considered the original object.

var x = 4,
    y = 4,
    tempEntry = { y, x },
    map1 = new Map;

map1.set(tempEntry, map1.has(tempEntry));
console.log([...map1]);

map1.set(tempEntry, map1.has(tempEntry)); // returns true
console.log([...map1]);

tempEntry = { y, x };

map1.set(tempEntry, map1.has(tempEntry)); // a new object
console.log([...map1]);

.as-console-wrapper { max-height: 100% !important; top: 0; }

A possible solution could involve serializing the object into a string, as long as the order of the keys remains the same.

var x = 4,
    y = 4,
    tempEntry = JSON.stringify({ y, x }),
    map1 = new Map;

map1.set(tempEntry, map1.has(tempEntry));
console.log([...map1]);

tempEntry = JSON.stringify({ y, x });

map1.set(tempEntry, map1.has(tempEntry)); // same object
console.log([...map1]);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Store a distinct identifier as an object within a JavaScript collection

Answer №1

Similar questions

"Exploring the use of jQuery to access dynamic CSS properties such as :before and implementing filter

Sending a Javascript object to PHP for decoding as JSON can be accomplished by

Unable to start node.js server to upload file in node with express and multer

Application with Single Page design has a Large DOM, leading to sluggish performance

Is it possible to assign a deconstructed array to a variable and then further deconstruct it?

What is the most effective way to obtain a customer's latitude and location by prompting them to drop a pin on Google Maps?

Using Ajax to return a Post type in c# mvc 4 instead of a value

Three divs are set in place, with two of them of fixed width while the third div is

Sorting functionality malfunctioning after dynamically adding new content using AJAX

Implement dynamic routes within your Nuxt single page application once it has been generated

The not:first-child selector targets all elements except for the first one in the sequence

Setting up Karma configuration to specifically exclude nested directories

Sending an Ajax request using a dropdown menu

The @mouse-down event in Vue does not seem to be firing

Issue encountered while validating password using regex pattern?

What is the method with the greatest specificity for applying styles: CSS or JS?

Data binding in AngularJS allows for easy synchronization between the model and the view

Using Angular directives to dynamically add event listeners with the ng-repeat directive

Node.js - Issue with res.json function: inconsistency across different routes

Navigating through the URL using an AJAX request with jQuery