Javascript copy of string

Force JavaScript to Deep Copy a String

1. What Is Deep Copy
2. How to Copy a String in JavaScript
3. How to Deep Copy a String in JavaScript

This article will discuss what a deep copy is, how to copy a string, and deep copy a string in JavaScript. We will also tackle the key difference between them.

What Is Deep Copy

In a deep copy, the whole string object is duplicated and stored in another string object. All the original string object contents are copied and stored in the new string object.

However, in copy, the original address is stored and accessed every time we access the copied string object.

How to Copy a String in JavaScript

When you copy a string, its address is stored in the specified String variable in JavaScript. Let’s look at this code segment to understand the concept better.

let original_string = 'Hello'; var string_copy = (' ' + original_string).slice(1); 

In this code segment, as you can see, there was a variable named original_string , which had a string value Hello .

The original string is used as a reference after a space ‘ ‘ . This concatenation results in a string copy in the browser’s implementation.

How to Deep Copy a String in JavaScript

In the mentioned explanation of the deep copy code segment, we have used a string prototype function called a slice, so let us explain the slice() prototype function first.

The slice method is used in JavaScript to retrieve a part of a string as a new string without changing the original string. Let’s see this code segment where we have used slice() :

let str = "Sliced_String"; let res = str.slice(0, 5); console.log(res); 

The first five characters from the string have been extracted and displayed on the console as an output. Note here that the arguments here are 0 indexed; hence, the 6th character is not extracted.

Alternatively, you can not provide any arguments that return the whole string as a new string.

Now, come back to the deep copy explanation.

As mentioned above, the deep copy in JavaScript duplicates the whole JavaScript string object and stores it in a specified string constant or variable. Let us look at this code segment where we have deep copied a JavaScript string object into a constant.

const str = 'I am showing an example'; const new_str = str.slice();  console.log( new_str ); 

In the code segment above, the program will not use the reference of the original string but will copy each character of the original string into the new string variable.

As explained above, the slice() function extracted the whole string from the str constant and returned it as a new string into the new_str constant. This new constant was shown as an output in the last line of the code segment using a console.log() .

Related Article — JavaScript String

Copyright © 2023. All right reserved

Источник

JavaScript Copy String Values: Mastering the Techniques for Deep and Shallow Copying

Learn the best methods for copying string values in Javascript, including deep and shallow copying, object cloning, and copying to the clipboard. Get the essential tips and examples to make your code more efficient.

• JavaScript’s slice() method for copying string values
• Forcing deep copying in JavaScript
• Copying objects in JavaScript
• Useful String object methods for copying string values
• Copying string values to the clipboard in JavaScript
• Copying variable values in JavaScript
• Other Quick Examples of Copying String Values in JavaScript
• Conclusion
• How to copy string value in JavaScript?
• How to copy variable value JavaScript?
• How do you copy values in a string?
• How to copy a part of a string in JavaScript?

JavaScript is a popular programming language used for web development. One of the fundamental tasks in JavaScript is copying string values. Copying a string value means creating a new string with the same value as the original string. In JavaScript, there are different techniques for copying string values, and it is essential to understand the differences between them to know when to use each technique.

JavaScript’s slice() method for copying string values

The slice() method is a built-in method of the string object in javascript . It can be used to make a shallow copy of a string. Shallow copying means creating a new string that shares the same memory reference as the original string. The slice() method takes two arguments, start and end , which specify the range of characters to copy. If end is not provided, the method copies to the end of the string.

const originalString = 'JavaScript is awesome'; const copiedString = originalString.slice(0); console.log(copiedString); // JavaScript is awesome 

Although the slice() method is straightforward to use, it has limitations when it comes to deep copying. Deep copying means creating a new string with a different memory reference from the original string.

Forcing deep copying in JavaScript

To force deep copying in javascript , you can add a space to the front of the string. This is a hack that works because adding a space to the front of a string creates a new memory reference for the string.

const originalString = 'JavaScript is awesome'; const copiedString = ' ' + originalString.slice(0); console.log(copiedString); // JavaScript is awesome 

However, this method has some drawbacks. It is not efficient for large strings because it creates a new string in memory. Also, it is not a widely known technique and can be confusing to other developers.

Copying objects in JavaScript

In JavaScript, simple values like strings are passed by value, which means that a copy of the value is created when it is assigned to a variable or passed as an argument to a function. However, objects and arrays are passed by reference, which means that a copy of the reference to the object or array is created, not a copy of the object or array itself.

To copy objects in JavaScript, you need to use a cloning technique that creates a new object with the same properties as the original object. There are different methods for cloning objects in javascript , including spread syntax, Object.assign() , and JSON.stringify() and JSON.parse() .

Spread syntax

Spread syntax is a new feature in JavaScript that allows you to spread the contents of an array or object literal into another array or object.

const originalObject = < name: 'John', age: 30 >; const copiedObject = < . originalObject >; console.log(copiedObject); //

Object.assign()

Object.assign() is a built-in method of the Object object in JavaScript. It can be used to copy the properties of one or more objects to a target object.

const originalObject = < name: 'John', age: 30 >; const copiedObject = Object.assign(<>, originalObject); console.log(copiedObject); //

JSON.stringify() and JSON.parse()

JSON.stringify() is a built-in method of the JSON object in JavaScript. It can be used to convert an object to a JSON string. JSON.parse() is a built-in method of the JSON object in JavaScript. It can be used to convert a JSON string to an object.

const originalObject = < name: 'John', age: 30 >; const copiedObject = JSON.parse(JSON.stringify(originalObject)); console.log(copiedObject); //

Useful String object methods for copying string values

In addition to the slice() method, there are other methods of the String object that can be used for copying string values.

toString()

toString() is a built-in method of the Object object in JavaScript. It can be used to convert an object to a string.

const originalString = 'JavaScript is awesome'; const copiedString = originalString.toString(); console.log(copiedString); // JavaScript is awesome 

replace()

replace() is a built-in method of the String object in JavaScript. It can be used to replace a substring in a string with another substring.

const originalString = 'JavaScript is awesome'; const copiedString = originalString.replace(/awesome/g, 'great'); console.log(copiedString); // JavaScript is great 

substr()

substr() is a built-in method of the String object in JavaScript. It can be used to extract a substring from a string.

const originalString = 'JavaScript is awesome'; const copiedString = originalString.substr(0); console.log(copiedString); // JavaScript is awesome 

Copying string values to the clipboard in JavaScript

Copying string values to the clipboard is a common task in JavaScript. To do this, you can create a new textarea element, fill it with the desired string, select the text, copy it, and then remove the textarea element.

function copyToClipboard(text) < const textarea = document.createElement('textarea'); textarea.value = text; textarea.style.position = 'fixed'; document.body.appendChild(textarea); textarea.select(); document.execCommand('copy'); document.body.removeChild(textarea); >const originalString = 'JavaScript is awesome'; copyToClipboard(originalString); 

Copying variable values in JavaScript

To copy variable values in JavaScript, you can use the same cloning techniques used for objects. For example, you can use spread syntax, Object.assign() , or JSON.stringify() and JSON.parse() .

const originalValue = 42; const copiedValue = ; console.log(copiedValue); // 42 

Other Quick Examples of Copying String Values in JavaScript

In Javascript as proof, copy string js code sample

 var dummyContent = "this is to be copied to clipboard"; var dummy = $('').val(dummyContent).appendTo('body').select() document.execCommand('copy')

Conclusion

In conclusion, copying string values is an essential task in JavaScript. There are different techniques for copying string values, including the slice() method, adding a space to the front of the string, cloning objects, and using String object methods. Understanding the differences between these techniques is crucial for writing efficient and effective JavaScript code.

Источник

Copy String Js With Code Examples

With this text, we’ll take a look at some examples of Copy String Js issues in programming.

const el = doc.createElement('textarea'); el.worth = str; //str is your string to repeat doc.physique.appendChild(el); el.choose(); doc.execCommand('copy'); // Copy command doc.physique.removeChild(el);

The actual downside Copy String Js may be fastened by using an alternate method, which is printed within the subsequent part together with some code samples for reference.

navigator.clipboard.writeText("your textual content right here")

var dummyContent = "that is to be copied to clipboard"; var dummy = $('').val(dummyContent).appendTo('physique').choose() doc.execCommand('copy')

Many examples helped us perceive the right way to repair the Copy String Js error.

How do I copy a string in JavaScript?

JavaScript: Copy a string to the clipboard

• Create a brand new factor, fill it with the provided knowledge and add it to the HTML doc.
• Use Selection. getRangeAt()to retailer the chosen vary (if any).
• Use Document.
• Remove the factor from the HTML doc.
• Finally, use Selection().

How do you copy a string?

How to repeat a string utilizing strcpy() operate in C

• The strcpy() operate is a built-in library operate, declared within the string. h header file.
• strcpy() takes two strings as arguments and character by character (together with ) copies the content material of string Src to string Dest, character by character. Execution.
• Code​

How do I make a deep copy of a string?

• Try operating typeof on that. It offer you an occasion of kind String fairly than the String primitive, which offers extra performance.
• Also, simply examined it, attempt doing strCopy = String(originalStr); then modify the unique string by doing strCopy[0] = “X” . Both copies might be modified.

How do you repeat a string?

JavaScript String repeat() The repeat() technique returns a string with plenty of copies of a string. The repeat() technique returns a brand new string. The repeat() technique doesn’t change the unique string.

Can you slice a string in JavaScript?

The slice() technique extracts part of a string. The slice() technique returns the extracted half in a brand new string. The slice() technique doesn’t change the unique string. The begin and finish parameters specifies the a part of the string to extract.

How do you narrow a string in Java?

Java String cut up() technique instance

How can I copy only a portion of a string?

We can use string operate strncpy() to repeat half strings. Part of the second string is added to the primary string.

How does strcpy () operate works?

The strcpy() operate copies string2, together with the ending null character, to the situation that’s specified by string1. The strcpy() operate operates on null-ended strings. The string arguments to the operate ought to comprise a null character () that marks the tip of the string. No size checking is carried out.

How do I copy a string to a pointer?

The strcpy() operate is used to repeat strings. It copies string pointed to by supply into the vacation spot . This operate accepts two arguments of kind pointer to char or array of characters and returns a pointer to the primary string i.e vacation spot .

What is deep copy in JS?

A deep copy of an object is a duplicate whose properties don’t share the identical references (level to the identical underlying values) as these of the supply object from which the copy was made.23-Apr-2022

Build with us Share this content

Источник