How to inpu save the contents of this field in the state history. History API?

Question

JavaScript

How to save the contents of this field in the state history with each change in the content of the input field.

userText.addEventListener("input", () => {
    document.getElementById("char-count").innerHTML = userText.value.length;
    saveState(userText);
});

function saveState(object) {
    history.pushState({ saved: object }, "Additional information");
}

console.log(history);

Why does not it work?
This example works, but the question is how to write the content?

history.pushState({foo: 'bar'}, 'Title', '/baz.html')

Should I use JSON in foo ?

Answer 1

I decided!
Only it is necessary that not by the piece, but the entire field is recorded

userText.addEventListener("input", () => {
    document.getElementById("char-count").innerHTML = userText.value.length;
    saveState(userText.value);
});

function saveState(object) {
    let objectJson = JSON.stringify(object);
    history.pushState({ page: objectJson }, "title", "?page");
    console.log(history);
}