Macro View of Map Internals In Go

Introduction

There are lots of posts that talk about the internals of slices, but when it comes to maps, we are left in the dark. I was wondering why and then I found the code for maps and it all made sense.

https://golang.org/src/runtime/hashmap.go (https://www.ardanlabs.com/broken-link)

At least for me, this code is complicated. That being said, I think we can create a macro view of how maps are structured and grow. This should explain why they are unordered, efficient and fast.

Creating and Using Maps

Let’s look at how we can use a map literal to create a map and store a few values: