Question

Not all operators are symbols. Some are written as words. One example is the typeof operator, which produces a string value naming the type of the value you give it.

console.log(typeof 4.5)
// → number
console.log(typeof "x")
// → string

We will use console.log in example code to indicate that we want to see the result of evaluating something. When you run such code, the value produced should be shown on the screen, though how it appears will depend on the JavaScript environment you use to run it.

The other operators we saw all operated on two values, but typeof takes only one. Operators that use two values are called binary operators, while those that take one are called unary operators. The minus operator can be used both as a binary operator and as a unary operator.

console.log(- (10 - 2))
// → -8

This is a book about getting computers to do what you want them to do. Computers are about as common as screwdrivers today, but they contain a lot more hidden complexity and thus are harder to operate and understand. To many, they remain alien, slightly threatening things.