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Finds the first item from an array, collection or enumerable object that matches the truth function and returns its key (that is the zero-based index number of an item in an array or the property name in an object).


list: TList<T> | undefined,
fn: (item: T) => boolean
): string | number | undefined


listT[] | undefinedNoSpecifies the array, collection or enumerable object to iterate through.
fn(item: T) => booleanNoSpecifies the truth function. Each item is supplied to the function, passing the item as argument. The function should return a boolean value whether to include the item in the selection.

Return value

Returns the item key or undefined if no item is found.


import { find } from "@tripetto/runner";

find<number>([1, 2, 3], (nItem: number) => nItem > 1); // Returns `1`
find<Object>({a: 1, b: 2, c: 3}, (nItem: number) => nItem > 1); // Returns `b`