console.log(history.length)

history.back()    // history.go(-1)

history.forward() // history.go(1)

history.go(-1)
history.go(1)

let currentState = history.state

let people = { names: ["Alice", "Charlie", "Bob"] }
history.pushState(people, "People", "people.html")

let people = { names: ["Alice", "Bob", "Charlie"] }
history.replaceState(people, "People Sorted", "people.html#sorted")