in packages/shared/src/array.ts [209:236]
export function findIndex<T>(
val: T[],
iterator: EachArrayIterator<T>,
revert?: boolean
): number
export function findIndex<T extends {}, TValue = T[keyof T]>(
val: T,
iterator: EachObjectIterator,
revert?: boolean
): keyof T
export function findIndex(
val: any,
iterator: any,
revert?: boolean
): string | number {
let res: number | string = -1
each(
val,
(item, key) => {
if (iterator(item, key)) {
res = key
return false
}
},
revert
)
return res
}