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This operator will return false if the expression on the right evaluates to true, and return true if the
expression on the right evaluates to false.

!x;

This will return false, because x is true.

Abstract Equality (==)

Operands of the abstract equality operator are compared after being converted to a common type.
How this conversion happens is based on the specification of the operator:

Specification for the == operator:

7.2.13 Abstract Equality Comparison

The comparison x == y, where x and y are values, produces true or false. Such a
comparison is performed as follows:

1. If Type(x) is the same as Type(y), then:

• a. Return the result of performing Strict Equality Comparison x === y.

2. If x is null and y is undefined, return true.
3. If x is undefined and y is null, return true.
4. If Type(x) is Number and Type(y) is String, return the result of the comparison x ==
ToNumber(y).
5. If Type(x) is String and Type(y) is Number, return the result of the comparison
ToNumber(x) == y.
6. If Type(x) is Boolean, return the result of the comparison ToNumber(x) == y.
7. If Type(y) is Boolean, return the result of the comparison x == ToNumber(y).
8. If Type(x) is either String, Number, or Symbol and Type(y) is Object, return the result
of the comparison x == ToPrimitive(y).
9. If Type(x) is Object and Type(y) is either String, Number, or Symbol, return the result
of the comparison ToPrimitive(x) == y.
10. Return false.

Examples:

1 == 1; // true
1 == true; // true (operand converted to number: true => 1)
1 == '1'; // true (operand converted to number: '1' => 1 )
1 == '1.00'; // true
1 == '1.00000000001'; // false
1 == '1.00000000000000001'; // true (true due to precision loss)
null == undefined; // true (spec #2)
1 == 2; // false
0 == false; // true
0 == undefined; // false

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