JavaScript

In JavaScript, you often need to search for a specific word or pattern inside a string. JavaScript provides several methods to help you find, locate, or match parts of a string easily.

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✅ Why Use String Search Methods?

Whether you’re checking if a word exists in a sentence, finding the position of a character, or matching a pattern using regular expressions, JavaScript’s string search tools have you covered.

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🔹 1. indexOf() – Finds the first occurrence

let text = "I love JavaScript!";
console.log(text.indexOf("JavaScript")); // Output: 7

• Returns the index of the first match.
• Returns -1 if the text is not found.

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🔹 2. lastIndexOf() – Finds the last occurrence

let text = "I love JavaScript. JavaScript is fun!";
console.log(text.lastIndexOf("JavaScript")); // Output: 18

• Useful when a word appears multiple times.

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🔹 3. search() – Searches using a regular expression

let text = "I love JavaScript!";
console.log(text.search(/script/i)); // Output: 10

• i makes the search case-insensitive.
• Similar to indexOf, but more powerful with regex.

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🔹 4. includes() – Checks if a string contains a value

let text = "Hello world!";
console.log(text.includes("world")); // Output: true

• Returns a boolean (true or false).
• Case-sensitive.

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🔹 5. startsWith() – Checks if string starts with given value

let text = "JavaScript is awesome!";
console.log(text.startsWith("Java")); // Output: true

• You can also pass a start position as the second argument.

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🔹 6. endsWith() – Checks if string ends with given value

let text = "Learn JavaScript";
console.log(text.endsWith("Script")); // Output: true

• Can also be used with a length argument to test within a portion of the string.

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✨ Bonus: Using Regular Expressions with match()

let text = "The rain in Spain";
let result = text.match(/ain/g); 
console.log(result); // Output: ["ain", "ain"]

• match() finds all matches of a pattern.
• g is the global flag (find all, not just the first).

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🧠 Summary Table

Method	Description	Returns
indexOf()	First position of a match	Number (-1 if not found)
lastIndexOf()	Last position of a match	Number
search()	Search using regex	Number
includes()	Checks if string contains value	Boolean
startsWith()	Checks beginning of string	Boolean
endsWith()	Checks end of string	Boolean
match()	Finds matches using regex	Array or null

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