Use the strict equality operator when comparing variables

When checking whether two given variables equal to each other, always use the strict equality (`===`) instead of the equality (`==`) operator.

The `===` operator not only checks the values, but also the types of variables. It's safer then `==` which performs type conversions before comparing the values.

0 == false; // true
0 === false; // false

0 == []; // true
0 === []; // false

0 == ''; // true
0 === ''; // false

You can take a look at == vs === to see more examples.