Why local variables are called "let"

2022 Jan 10

In JavaScript there are 3 different kinds of variables, global variables(using var), constants(const, and local variables(let). All of the act allittle differently from eachother. Allow me to explain what they do.

Global variables, made using var, are as they sound, global variables. Once defined, they can be used, edited, or redefind anywhere.

Constants, defined with const, are constant, they cannot change, at all.

Local variables, defined with let, are variables that can only be used in the place that it is defined, like a function, and it's children.

Now that we has that established, let's talk about how local variables got their name.

Turns out "let" is a mathematical term. The "let" expression may also be defined in mathematics, where it associates a Boolean condition with a restricted scope. [source]. It was first used in programming in early languages like Basic.

In case you're wondering, the main source is this answer on Stack Overflow.