This blog post explores JavaScript strings. We’ll look at how to make them, change them, and use some common string methods. We’ll also show code examples.
1. Making a String
You can make strings with single quotes (‘) double quotes (“), or backticks (`).
Example:
<script> let str1 = 'Hello'; let str2 = "World"; let str3 = `Hello, ${str2}!`; console.log(str1); // Output: Hello console.log(str2); // Output: World console.log(str3); // Output: Hello World! </script>
2. String Length
To find out how many characters a string has, you can use the length property.
Example:
<script> let message = "JavaScript"; console.log(message.length); // Output: 10 </script>
3. Getting Characters
You can get individual characters in a string using bracket notation or the charAt() method.
Example:
<script> let greeting = "Hello"; console.log(greeting[1]); // Output: e console.log(greeting.charAt(1)); // Output: e </script>
4. Joining Strings
You can combine strings using the + operator or the concat() method.
Here’s an example:
<script> let firstName = "John"; let lastName = "Doe"; let fullName = firstName + " " + lastName; console.log(fullName); // Output: John Doe let full = firstName.concat(" ", lastName); console.log(full); // Output: John Doe </script>
5. Changing Case
You can use toUpperCase() and toLowerCase() to alter the case of strings.
Here’s an example:
<script> let text = "JavaScript"; console.log(text.toUpperCase()); // Output: JAVASCRIPT console.log(text.toLowerCase()); // Output: javascript </script>
6. Trimming Whitespace
To remove whitespace, you can apply trim() trimStart(), and trimEnd().
Check out this example:
<script> let spaced = " Hello World "; console.log(spaced.trim()); // Output: Hello World </script>
7. Searching in a String
To look for substrings, you can use indexOf() lastIndexOf(), and includes().
Take a look at this example:
<script> let phrase = "Learn JavaScript"; console.log(phrase.indexOf("Java")); // Output: 6 console.log(phrase.includes("Script")); // Output: true </script>
8. Extracting Substrings
You can extract parts of a string using substring() slice(), or substr().
Here’s an example:
<script> let example = "JavaScript"; console.log(example.substring(0 4)); // Output: Java console.log(example.slice(4)); // Output: Script </script>
9. Changing Text
You can use replace() or replaceAll() to swap out parts of a string.
Here’s an example:
<script> let str = "I like cats"; let newStr = str.replace("cats", "dogs"); console.log(newStr); // Output: I like dogs </script>
10. Breaking a String into Pieces
The split() method turns a string into an array.
Check out this example:
<script> let data = "apple,banana cherry"; let items = data.split(","); console.log(items); // Output: ["apple", "banana", "cherry"] </script>
To wrap up
JavaScript strings are flexible and come with many built-in methods to handle and process text. Getting to grips with how to make and use these methods, you can handle a wide variety of tasks in web development efficiently.