src/Primitive/Container/Container.php
public function search($value, $strict = false)
    {
        return Arr::search($this->items, $this->getSearchable($value, $value), $this->getBoolable($strict));
    }
public function search($value, $strict = false)
    {
        return Arr::search($this->items, $this->getSearchable($value, $value), $this->getBoolable($strict));
    }
Search for specified value, return key on success, otherwise false.
If value is nested deeper than 1 level dot notation key will be returned.
You can specify strict search with 2 argument.

@param mixed $value
@param bool|BooleanContract $strict
@return mixed