Adopt type: module.

[mbostock]

Fixes #3502.
Fixes #3501.
Fixes #3469.
Fixes #3477.
Fixes #3454.
Fixes #3366.

[arthurblake-AngelOak]

The main README still notes node usage for CJS which is now broken

In Node:

const d3 = require("d3");

You can also require individual modules and combine them into a d3 object using Object.assign:

const d3 = Object.assign({}, require("d3-format"), require("d3-geo"), require("d3-geo-projection"));