This example demonstrates how to merge and compare arrays in JavaScript using nested `forEach` loops. It starts with two arrays of state objects—one containing names and locations, another with names and IDs—and matches them by name to assign the appropriate ID to each object in the first array. It then compares two simple arrays of letters, logging any common elements to the console. The visualization relies entirely on the browser’s console output, using no D3 APIs or rendering, despite loading d3.v4. The code is written in plain JavaScript and produces no visual graphics.