2.7 Operators

Many operators are known to us from school. They are addition +, a multiplication *, a subtraction - and so on.

In this chapter we concentrate on aspects that are not covered by school arithmetic.

Terms: “unary”, “binary”, “operand”

Before we move on, let’s grasp the common terminology.

• An operand – is what operators are applied to. For instance in multiplication 5 * 2 there are two operands: the left operand is 5, and the right operand is 2. Sometimes people say “arguments” instead of “operands”.

• An operator is unary if it has a single operand. For example, the unary negation - reverses the sign of the number:

  let x = 1;
  
  x = -x;
  alert( x ); // -1, unary negation was applied
  

• An operator is binary if it has two operands. The same minus exists in the binary form as well:

  let x = 1, y = 3;
  alert( y - x ); // 2, binary minus subtracts values
  

Formally, we’re talking about two different operators here: the unary negation (single operand, reverses the sign) and the binary subtraction (two operands, subtracts).