Function findIndex

findIndex<T>(object, fn): number
Find the index of the first value which matches a predicate.
Type Parameters
- T
Parameters
- object: Iterable<T>
  The iterable object to search.
- fn: ((value, index) => boolean)
  The predicate function to apply to the values.
  - - (value, index): boolean
    - Parameters
      value: T
      index: number
      Returns boolean
Returns number
The index of the first matching value, or -1 if no matching value is found.

Complexity
Linear.

Example
```
import { findIndex } from '@lumino/algorithm';

interface IAnimal { species: string, name: string };

function isCat(value: IAnimal): boolean {
  return value.species === 'cat';
}

let data: IAnimal[] = [
  { species: 'dog', name: 'spot' },
  { species: 'cat', name: 'fluffy' },
  { species: 'alligator', name: 'pocho' }
];

findIndex(data, isCat);  // 1
```
- Defined in find.ts:88