JSFiddle - React, Tailwind, and code Playground

JavaScript

// Consistently speaking, all third sets should be the same in each case

console.log(
    "append disconnected: ",
    $("<div>"),
    $("<div>").append("a"),
    $("<div>").append("a").end()
);

console.log(
    "after  disconnected: ",
    $("<div>"),
    $("<div>").after("a"),
    $("<div>").after("a").end()  // same set as without .end() ?!
);

console.log("---");

console.log(
    "append connected: ",
    $("<div>").appendTo("body"),
    $("<div>").appendTo("body").append("a"),
    $("<div>").appendTo("body").append("a").end()
);

console.log(
    "after  connected: ",
    $("<div>").appendTo("body"),
    $("<div>").appendTo("body").after("a"),
    $("<div>").appendTo("body").after("a").end()
);

console.log("---");

console.log(
    "append empty set: ",
    $(),
    $().append("a"),
    $().append("a").end()
);

console.log(
    "after  empty set: ",
    $(),
    $().after("a"),
    $().after("a").end()  // same as without .end() ?!
);