JavaScript String Search Methods

While working with strings, we often need to find whether a particular word exists inside a string, determine its position, or check how a string starts or ends.

For this purpose, JavaScript provides several String Search Methods.

In this article, we will learn the most commonly used string search methods with syntax, arguments, examples, and outputs.

indexOf()

The indexOf() method returns the position of the first occurrence of a specified value in a string.

If the value is not found, it returns -1.

Syntax

string.indexOf(searchValue, startIndex)

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Arguments

searchValue: The text you want to search for.

startIndex (Optional): The position from where searching should begin. Default value is 0.

Example

let text = "Learn JavaScript";
console.log(text.indexOf("Java"));

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Output

The word “Java” starts at index position 6.

Example: Value Not Found

let text = "Learn JavaScript";
console.log(text.indexOf("Python"));

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Output

-1

lastIndexOf()

The lastIndexOf() method returns the position of the last occurrence of a specified value.

If the value is not found, it returns -1.

Syntax

string.lastIndexOf(searchValue, startIndex)

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Arguments

searchValue: The text to search.

startIndex (Optional): The position from where searching starts backwards.

Example

let text = "Java JavaScript Java";
console.log(text.lastIndexOf("Java"));

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Output

The last occurrence of “Java” begins at index position 16.

includes()

The includes() method checks whether a specified value exists inside a string.

It returns either true or false.

Syntax

string.includes(searchValue, startIndex)

Arguments

searchValue: The value to search.

startIndex (Optional): Position from where searching should start.

Example

let text = "Learn JavaScript";
console.log(text.includes("Java"));

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Output

true

Example

let text = "Learn JavaScript";
console.log(text.includes("Python"));

Output

false

startsWith()

The startsWith() method checks whether a string starts with a specified value.

It returns true or false.

Syntax

string.startsWith(searchValue, startIndex)

Arguments

searchValue: The text to check.

startIndex (Optional): Position from where checking should begin.

Example

let text = "Learn JavaScript";
console.log(text.startsWith("Learn"));

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Output

true

Example

let text = "Learn JavaScript";
console.log(text.startsWith("Java"));

Output

false

endsWith()

The endsWith() method checks whether a string ends with a specified value.

Syntax

string.endsWith(searchValue, length)

Arguments

searchValue: The text to check.

length (Optional): Specifies the length of the string to consider.

Example

let text = "Learn JavaScript";
console.log(text.endsWith("Script"));

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Output

true

Example

let text = "Learn JavaScript";
console.log(text.endsWith("Java"));

Output

false

search()

The search() method searches a string and returns the position of the first match.

If no match is found, it returns -1.

Syntax

string.search(searchValue)

Arguments

searchValue: The text or regular expression to search.

Example

let text = "Learn JavaScript";
console.log(text.search("Java"));

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Output

match()

The match() method searches a string and returns matching results.

Syntax

string.match(searchValue)

Arguments

searchValue: The string or regular expression to search.

Example

let text = "Learn JavaScript";
console.log(text.match("Java"));

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Output

[“Java”]

matchAll()

The matchAll() method returns all matches from a string. It is mainly used with Regular Expressions.

Syntax

string.matchAll(pattern)

Arguments

pattern: A regular expression used for matching.

Example

let text = "Java Java Java";
console.log([...text.matchAll(/Java/g)]);

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Output

[

[“Java”],

[“Java”]

]

All occurrences of “Java” are returned.

Summary

These methods help us search, locate, and verify text within strings and are commonly used in form validation, filtering, searching, and data processing.

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