Random example, imagine a variable that holds the time of the last time the user moved the mouse. Or in a game holding the current selected target of the player. Or the players gold amount. Or its level. Or health. Or current position.
Keeping state managed. The data for the function will be very predictable. This is especially important when it comes to multithreading. You can’t have a race condition where two things update the same data when they never update it that way at all.
Rather than me coming up with an elaborate and contrived example, I suggest giving a language like Elixir a try. It tends to force you into thinking in terms of immutability. Bit of a learning curve if you’re not used to it, but it just takes practice.
That is a… strange take.
Random example, imagine a variable that holds the time of the last time the user moved the mouse. Or in a game holding the current selected target of the player. Or the players gold amount. Or its level. Or health. Or current position.
In all those cases, the answer is to swap in a new variable and throw the old one away.
Legit question because i think I’m misunderstanding. But if its a const, how are you able to swap or replace it?
It’s only a const within a function. You can pass the value to another function and changing it as it’s passed. For example:
In functional programming, you tend to keep track of state on the stack like this.
Aaah okay i get it now :) that makes a lot more sense.
What is the advantage of this VS just overwriting the var?
Keeping state managed. The data for the function will be very predictable. This is especially important when it comes to multithreading. You can’t have a race condition where two things update the same data when they never update it that way at all.
Hm I’m having trouble visualizing this do you know a quick little example to illustrate this?
Rather than me coming up with an elaborate and contrived example, I suggest giving a language like Elixir a try. It tends to force you into thinking in terms of immutability. Bit of a learning curve if you’re not used to it, but it just takes practice.
Ok how about this then, I frequently do something like this:
let className = 'btn' if (displayType) { className += ` ${displayType}` } if (size) { className += ` ${size}` } if (bordered) { className += ' border' } if (classNameProp) { className += ` ${classNameProp}` }How would this be made better with a functional approach? And would be more legible, better in anyway?