Illuminate\Support\Collection::containsStrict PHP Method

    public function containsStrict($key, $value = null)
    {
        if (func_num_args() == 2) {
            return $this->contains(function ($item) use($key, $value) {
                return data_get($item, $key) === $value;
            });
        }
        if ($this->useAsCallable($key)) {
            return !is_null($this->first($key));
        }
        return in_array($key, $this->items, true);
    }

 public function testContainsStrict()
 {
     $c = new Collection([1, 3, 5, '02']);
     $this->assertTrue($c->containsStrict(1));
     $this->assertFalse($c->containsStrict(2));
     $this->assertTrue($c->containsStrict('02'));
     $this->assertTrue($c->containsStrict(function ($value) {
         return $value < 5;
     }));
     $this->assertFalse($c->containsStrict(function ($value) {
         return $value > 5;
     }));
     $c = new Collection([['v' => 1], ['v' => 3], ['v' => '04'], ['v' => 5]]);
     $this->assertTrue($c->containsStrict('v', 1));
     $this->assertFalse($c->containsStrict('v', 2));
     $this->assertFalse($c->containsStrict('v', 4));
     $this->assertTrue($c->containsStrict('v', '04'));
     $c = new Collection(['date', 'class', (object) ['foo' => 50], '']);
     $this->assertTrue($c->containsStrict('date'));
     $this->assertTrue($c->containsStrict('class'));
     $this->assertFalse($c->containsStrict('foo'));
     $this->assertFalse($c->containsStrict(null));
     $this->assertTrue($c->containsStrict(''));
 }