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Alfred Nwanokwai
Alfred Nwanokwai

Posted on • Originally published at Medium on

JavaScript String Methods: 20 Essential Techniques for Effective String Manipulation

javascript string method
source: instagram | codeauthor_

Welcome to my blog post where we’ll dive into the world of JavaScript string methods. Strings play a crucial role in JavaScript, and having a strong grasp of the available string manipulation techniques is essential for any developer. In this comprehensive guide, we will explore 20 powerful JavaScript string methods that will empower you to handle strings with ease and efficiency. Get ready to unlock the full potential of JavaScript string methods and take your coding skills to the next level!

  1. String Length (length): The length property allows you to determine the number of characters in a string. Here’s an example:

const message = "Hello, world!";
console.log(message.length); // Output: 13

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  1. Concatenation (concat): The concat() method combines two or more strings, creating a new string. Here’s an example:
const str1 = "Hello";
const str2 = "World";
const concatenatedStr = str1.concat(", ", str2);
console.log(concatenatedStr); // Output: Hello, World
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  1. Extracting Substrings (substring): The substring() method extracts a portion of a string based on specified start and end indexes. Here’s an example:
const sentence = "JavaScript is amazing!";
const extractedStr = sentence.substring(0, 10);
console.log(extractedStr); // Output: JavaScript
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  1. Searching for Substrings (indexOf): The indexOf() method locates the first occurrence of a specified substring within a string. Here’s an example:
const sentence = "JavaScript is amazing!";
const index = sentence.indexOf("is");
console.log(index); // Output: 11
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  1. Replacing Substrings (replace): The replace() method substitutes specific substrings within a string with new values. Here’s an example:
const sentence = "JavaScript is amazing!";
const newSentence = sentence.replace("amazing", "incredible");
console.log(newSentence); // Output: JavaScript is incredible!
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  1. Converting to Uppercase (toUpperCase): The toUpperCase() method transforms all characters in a string to uppercase. Here’s an example:
const message = "Hello, world!";
const uppercaseMsg = message.toUpperCase();
console.log(uppercaseMsg); // Output: HELLO, WORLD!
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  1. Converting to Lowercase (toLowerCase): The toLowerCase() method converts all characters in a string to lowercase. Here’s an example:
const message = "Hello, world!";
const lowercaseMsg = message.toLowerCase();
console.log(lowercaseMsg); // Output: hello, world!
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  1. Checking the Start of a String (startsWith): The startsWith() method verifies if a string starts with a particular substring. Here’s an example:
const sentence = "JavaScript is amazing!";
console.log(sentence.startsWith("JavaScript")); // Output: true
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  1. Checking the End of a String (endsWith): The endsWith() method checks if a string ends with a specified substring. Here’s an example:
const sentence = "JavaScript is amazing!";
console.log(sentence.endsWith("amazing!")); // Output: true
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  1. Trimming Whitespace (trim): The trim() method removes whitespace from the beginning and end of a string. Here’s an example:
const message = " Hello, world! ";
const trimmedMsg = message.trim();
console.log(trimmedMsg); // Output: Hello, world!
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  1. Splitting a String (split): The split() method divides a string into an array of

substrings based on a specified separator. Here’s an example:

const sentence = "JavaScript is amazing!";
const words = sentence.split(" ");
console.log(words); // Output: ["JavaScript", "is", "amazing!"]
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  1. Extracting Characters (charAt): The charAt() method retrieves the character at a specific index within a string. Here’s an example:
const word = "Hello";
console.log(word.charAt(1)); // Output: e
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  1. Extracting Unicode Values (charCodeAt): The charCodeAt() method returns the Unicode value of a character at a specified index. Here’s an example:
const word = "Hello";
console.log(word.charCodeAt(0)); // Output: 72
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  1. Checking if a String Contains a Substring (includes): The includes() method checks if a string contains a specific substring. Here’s an example:
const sentence = "JavaScript is amazing!";
console.log(sentence.includes("is")); // Output: true
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  1. Checking if a String Matches a Pattern (match): The match() method, used with regular expressions, determines if a string matches a particular pattern. Here’s an example:
const sentence = "JavaScript is amazing!";
const pattern = /is/;
console.log(sentence.match(pattern)); // Output: ["is"]
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  1. Repeating a String (repeat): The repeat() method repeats a string a specified number of times. Here’s an example:
const word = "Hello";
console.log(word.repeat(3)); // Output: HelloHelloHello
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  1. Extracting the Last Index of a Substring (lastIndexOf): The lastIndexOf() method finds the last occurrence of a substring within a string. Here’s an example:
const sentence = "JavaScript is amazing!";
console.log(sentence.lastIndexOf("a")); // Output: 15
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  1. Extracting a Subset of Characters (slice): The slice() method extracts a portion of a string based on specified start and end indexes. Here’s an example:
const word = "Hello";
const subset = word.slice(1, 4);
console.log(subset); // Output: ell
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  1. Checking if a String is Empty (isEmpty): The isEmpty() method checks if a string is empty. Here’s an example:
function isEmpty(str) {
 return str === "";
}
console.log(isEmpty("")); // Output: true
console.log(isEmpty("Hello")); // Output: false
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  1. Checking if a String is a Number (isNaN): The isNaN() method determines if a string represents a valid number. Here’s an example:
console.log(isNaN("123")); // Output: false
console.log(isNaN("Hello")); // Output: true
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Congratulations on learning about these 20 essential JavaScript string methods! With these techniques in your arsenal, you are now equipped to handle string manipulation tasks efficiently. Experiment with these methods, explore their variations, and apply them to solve real-world programming challenges. String manipulation is a fundamental aspect of JavaScript development, and by mastering these methods, you’ll enhance your coding skills and become a more proficient JavaScript developer. Happy coding!

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