Truthiness and equality

Terminology

Boolean values

true or false (there is no maybe).

Coercion

Implicitly converting a value from one type to another.

Falsy

A falsy (sometimes written falsey) value is a value that is considered false when converted to a Boolean value.

Truthy

A truthy value is a value that is considered true when converted to a Boolean value.

Equality (==)

The equality operator checks whether its two operands are equal, returning a Boolean result. Unlike the strict equality operator, it attempts to convert and compare operands that are of different types.

Inequality (!=)

The inequality operator checks whether its two operands are not equal, returning a Boolean result. Unlike the strict inequality operator, it attempts to convert and compare operands that are of different types.

Strict Equality (===)

The strict equality operator checks whether its two operands are equal, returning a Boolean result. Unlike the equality operator, the strict equality operator always considers operands of different types to be different.

String Inequality (!==)

The strict inequality operator (!==) checks whether its two operands are not equal, returning a Boolean result. Unlike the inequality operator, the strict inequality operator always considers operands of different types to be different.