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JavaScript/Typescript - 16 Topics

DEEP DIVE INTO

JavaScript/Typescript

Topic:slice() method

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The slice() method in JavaScript is used to extract a portion of a string and return it as a new string, without modifying the original string. It takes one or two arguments: the start and end indices for the slice. The slice() method is very useful for working with substrings. Here's a deep dive into the slice() method in JavaScript:

Syntax:

javascriptstring.slice(start);
string.slice(start, end);
  • string: The string from which you want to extract a substring.

  • start: The index at which the extraction begins. If negative, it counts from the end of the string.

  • end (optional): The index at which the extraction ends (but doesn't include the character at this index). If omitted, extraction goes up to the end of the string. If negative, it counts from the end of the string.

Basic Example:

javascriptconst text = "Hello, World!";
const slicedText = text.slice(7, 12);
console.log(slicedText); // "World"

In this example, the slice() method extracts characters from index 7 to index 12 (exclusive) from the text string and returns a new string with those characters.

Using Negative Indices:

Negative indices are used to count positions from the end of the string:

javascriptconst text = "Hello, World!";
const slicedText = text.slice(-6, -1);
console.log(slicedText); // "World"

The slice() method with negative indices extracts characters starting from the third last character to the first last character (exclusive) and returns them in a new string.

Omitted End Index:

When you omit the end index, the slice() method continues extracting characters until the end of the string:

javascriptconst text = "Hello, World!";
const slicedText = text.slice(7);
console.log(slicedText); // "World!"

Here, the slice() method starts at index 7 and extracts characters until the end of the text string.

Returning a New String:

The slice() method returns a new string containing the extracted characters. It does not modify the original string.

Non-Mutating and Immutability:

slice() is a non-mutating method, which means it does not change the original string. It's a useful tool for working with immutable data structures.

Use Cases:

  • Extracting substrings from a larger string.

  • Trimming or extracting portions of text.

  • Creating a copy of a string without modifying the original.

The slice() method is a versatile tool for working with substrings in JavaScript. It is commonly used in text manipulation, string manipulation, and various other scenarios where you need to extract specific portions of a string.

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