findIndex#

Finds the first index of the substr in the str. If not found, returns -1.

Usage Scenarios#

• Text Search: In text processing, find the position of a specific substring.
• Data Validation: Check if a substring exists in a string and get its position.

Example#

import { findIndex } from 'funtool/string'

findIndex('hello world', 'world'); // ✅ 6
findIndex('abc', 'z'); // ❌ -1

Signature#

function findIndex(str: string, substr: string): number

Parameters#

• str ( string ): The input string.
• substr ( string ): The substring to find.

Returns#

• ( number ): The index of the first occurrence of the substring, or -1 if not found.