isNode

Determines if the current runtime environment is Node.js.

• Use the process global object that provides information about the current Node.js process.
• Check if process, process.versions and process.versions.node are defined.

const isNode = () =>
  typeof process !== 'undefined' &&
  !!process.versions &&
  !!process.versions.node;

isNode(); // true (Node)
isNode(); // false (browser)