Creating a Substring from a String in JavaScript

When working with strings in JavaScript, you may often need to extract a part of a string to use in your code. This is where the substring() method comes in handy. The substring() method allows you to extract a portion of a string and create a new string from that portion.

Let’s take a look at how you can use the substring() method to create a substring from a string in JavaScript:

    
    // Example string
    const originalString = 'Hello, World!';

    // Using substring() to create a substring
    const substring = originalString.substring(7, 12);

    // Output the substring
    console.log(substring); // Output: "World"
    
    

In the example above, we have a string 'Hello, World!'. We are using the substring() method to create a substring that starts at index 7 (the ‘W’ in ‘World’) and ends at index 12 (the end of the string). The result is the substring 'World'.

The syntax for the substring() method is string.substring(startIndex, endIndex), where startIndex is the index to start the substring and endIndex is the index to end the substring (not inclusive).

It’s important to note that if you don’t specify an endIndex, the substring() method will automatically use the end of the string as the end index. For example:

    
    // Using substring() with only a start index
    const newSubstring = originalString.substring(7);

    // Output the new substring
    console.log(newSubstring); // Output: "World!"
    
    

In this case, we are specifying only the startIndex and not the endIndex. The substring() method will use the end of the string as the end index, resulting in the substring 'World!'.

So, as you can see, the substring() method is a useful tool for creating substrings from strings in JavaScript. It allows you to extract specific portions of a string and use them in your code as needed.