contains

Checks if a string contains a substring.

contains

Signature

function contains(str: string, substring: string, ignoreCase: boolean = false): boolean

Parameters

• str - The string to search in
• substring - The substring to search for
• ignoreCase - If true, case-insensitive search (default: false)

Returns

true if the substring is found, false otherwise.

Examples

import { contains } from 'strio'

// Basic usage
contains('hello world', 'world')
// true

contains('hello world', 'foo')
// false

// Case sensitive (default)
contains('Hello World', 'world')
// false

// Case insensitive
contains('Hello World', 'world', false)
// true

// Empty substring
contains('hello', '')
// true

// At the beginning
contains('hello world', 'hello')
// true

// At the end
contains('hello world', 'world')
// true

Use Cases

import { contains } from 'strio'

// Search functionality
function searchProducts(products: string[], query: string): string[] {
  return products.filter(p => contains(p.toLowerCase(), query.toLowerCase()))
}

// Validation
function hasProhibitedWords(text: string, words: string[]): boolean {
  return words.some(word => contains(text.toLowerCase(), word.toLowerCase()))
}

// Feature detection
function hasFeature(features: string, feature: string): boolean {
  return contains(features, feature, false)
}

Related Functions

• containsAll - Check if contains all substrings
• containsAny - Check if contains any substring
• count - Count occurrences

See Also

• String Validation Guide
• API Reference