Combining two or more entities is a typical activity in JavaScript, whether you’re interfacing with an API or overseeing states in client-side applications. JavaScript offers several methods to combine objects. This post will delve into object combination and the various techniques for merging objects in JavaScript.
Object merging involves the integration of two or more objects into a new object. This can be divided into two categories:
Superficial Merging
Profound Merging
JavaScript offers numerous methods to accomplish both types of merges. Let’s investigate each method individually:
Superficial Merging
Superficial merging is beneficial when you need to merge flat objects (objects that don’t include nested entities). There are two approaches to achieve superficial merging:
Utilizing Spread Operator { … }
Spread Operator { … } is a built-in feature in JavaScript. It is a contemporary and concise method to combine objects. It generates a new object and duplicates all properties from the initial object into the new object.
Sample:
Javascript
Code Copied!
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editor72367.clearSelection();
editor72367.setOptions({
maxLines: Infinity
});
function decodeHTML72367(input) {
var doc = new DOMParser().parseFromString(input, “text/html”);
return doc.documentElement.textContent;
}
// Function to copy code to clipboard
function copyCodeToClipboard72367() {
const code = editor72367.getValue(); // Get code from the editor
navigator.clipboard.writeText(code).then(() => {
jQuery(“.maineditor72367 .copymessage”).show();
setTimeout(function() {
jQuery(“.maineditor72367 .copymessage”).hide();
}, 2000);
}).catch(err => {
console.error(“Error copying code: “, err);
});
}
function runCode72367() {
var code = editor72367.getSession().getValue();
function closeoutput72367() {
var code = editor72367.getSession().getValue();
jQuery(".maineditor72367 .code-editor-output").hide();
}
// Attach event listeners to the buttons
document.getElementById("copyBtn72367").addEventListener("click", copyCodeToClipboard72367);
document.getElementById("runBtn72367").addEventListener("click", runCode72367);
document.getElementById("closeoutputBtn72367").addEventListener("click", closeoutput72367);
Result:
Clarification: This example illustrates two entities. The first is obj1, which includes name and year attributes. The second entity, obj2, holds name and course attributes. Both entities are combined using the spread operator {…}, resulting in new entities that encompass all combined attributes.
Key Reminder:
Combining objects with the spread operator produces a new entity.
If attributes are duplicated in both entities, values from the latter entity take precedence over the earlier ones.
Employing Object.assign() Method
Object.assign()…“`html
represents an alternative approach to amalgamate objects in JavaScript. It duplicates the attributes from one or more source objects to a destination object.
Illustration:
Javascript
Code Duplicated!
var isMobile = window.innerWidth “);
editor76944.setValue(decodedContent); // Assign the default text
editor76944.clearSelection();
editor76944.setOptions({
maxLines: Infinity
});
function decodeHTML76944(input) {
var doc = new DOMParser().parseFromString(input, “text/html”);
return doc.documentElement.textContent;
}
// Function to duplicate code to clipboard
function copyCodeToClipboard76944() {
const code = editor76944.getValue(); // Retrieve code from the editor
navigator.clipboard.writeText(code).then(() => {
// alert(“Code duplicated to clipboard!”);
function closeoutput76944() {
var code = editor76944.getSession().getValue();
jQuery(".maineditor76944 .code-editor-output").hide();
}
// Attach event listeners to the buttons
document.getElementById("copyBtn76944").addEventListener("click", copyCodeToClipboard76944);
document.getElementById("runBtn76944").addEventListener("click", runCode76944);
document.getElementById("closeoutputBtn76944").addEventListener("click", closeoutput76944);
Outcome:
Clarification: In this illustration, the Object.assign() function is employed to merge two objects. Here, in Object.assign({}, obj1, obj2), the initial object ( {}) serves as the destination object, while the remainder ( obj1, obj2 ) are termed source objects.
Significant Note:
Like the spread operator, in cases where both objects share identical properties, the attributes from the last object take precedence over the prior object’s attributes.
Comprehensive Merging
Superficial merging fails to operate when the object has a nested object (an object contained within another object). To combine such objects, you are required to carry out comprehensive merging utilizing the Lodash library in JavaScript.
Leveraging Lodash.merge() Function
Lodash is a contemporary utility library for JavaScript that offers a merge() function to execute comprehensive merging in JavaScript.
Illustration:
Javascript
Code Duplicated!
var isMobile = window.innerWidth “);
editor51616.setValue(decodedContent); // Assign the default text
editor51616.clearSelection();
editor51616.setOptions({
maxLines: Infinity
});
function decodeHTML51616(input) {
var doc = new DOMParser().parseFromString(input, “text/html”);
return doc.documentElement.textContent;
}
// Function to duplicate code to clipboard
function duplicateCodeToClipboard51616() {
const code = editor51616.getValue(); // Retrieve code from the editor
navigator.clipboard.writeText(code).then(() => {
// alert(“Code duplicated to clipboard!”);
function closeOutput51616() {
var code = editor51616.getSession().getValue();
jQuery(".maineditor51616 .code-editor-output").hide();
}
// Attach event listeners to the buttons
document.getElementById("copyBtn51616").addEventListener("click", duplicateCodeToClipboard51616);
document.getElementById("runBtn51616").addEventListener("click", executeCode51616);
document.getElementById("closeoutputBtn51616").addEventListener("click", closeOutput51616);
Result:
Clarification: .merge() function thoroughly merges all attributes. You need to first require lodash to utilize its .merge() function.
Combining Arrays Within Objects
By default, the Lodash merge() function does not join arrays. However, if you possess an object housing an array, you must resort to the mergeWith() method to combine those objects.
Demonstration:
Javascript
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editor46643.setValue(decodedContent); // Establish the default text
editor46643.clearSelection();
editor46643.setOptions({
maxLines: Infinity
});
function decodeHTML46643(input) {
var doc = new DOMParser().parseFromString(input, "text/html");
return doc.documentElement.textContent;
}
// Function to duplicate code to clipboard
function duplicateCodeToClipboard46643() {
const code = editor46643.getValue(); // Retrieve code from the editor
navigator.clipboard.writeText(code).then(() => {
// alert("Code duplicated to clipboard!");
function closeOutput46643() {
var code = editor46643.getSession().getValue();
jQuery(".maineditor46643 .code-editor-output").hide();
}
// Attach event listeners to the buttons
document.getElementById("copyBtn46643").addEventListener("click", duplicateCodeToClipboard46643);
document.getElementById("runBtn46643").addEventListener("click", executeCode46643);
document.getElementById("closeoutputBtn46643").addEventListener("click", closeOutput46643);
Result:
Clarification: .merge() by itself would replace the numbers array rather than merging it. Therefore, the mergeWith() function is utilized to combine an object containing an array within it.
Final Thoughts
Combining objects in JavaScript can be achieved through various methods, such as using the spread operator { …
```} or Object.assign() function for superficial merging and for comprehensive merging Lodash library is commonly utilized. To deepen your understanding of JavaScript and tackle interview preparations, check out our JavaScript Interview Questions document, curated by professionals in the field.
How to Combine Two Objects in JavaScript – FAQs
Q1. How can you append properties from one object to another in JavaScript?
You can utilize Object.assign(target, source) or the spread operator {…obj1, …obj2} to append properties of one object to a different object.
Q2. What is the quickest method to combine two objects in JavaScript?
For shallow merging, the spread operator (…) is the quickest and easiest to read method.
Q3. How can two nested objects be combined in JavaScript?
You may employ the .merge() function from the Lodash Library to combine two nested objects in JavaScript.
Q4. What is a substitute for Lodash?
The es-toolkit can be used instead of the Lodash library.
Q5. How do Object.assign and the spread operator differ?
Both perform shallow merging; however, Object.assign() alters the target object, whereas the spread operator generates a new object.
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