top level variables are reactive even when updated inside a function, just give it a try: https://svelte.dev/repl/44e3aece18294ddb834bcdfb4394af48?version=3.57

top level variables are reactive even when updated inside a function, just give it a try: https://svelte.dev/repl/44e3aece18294ddb834bcdfb4394af48?version=3.57.0 https://svelte.dev/repl/44e3aece18294ddb834bcdfb4394af48?ver... ` <script> let name = 'world'; const flip = () => name = name === name.toUpperCase() ? name.toLowerCase() : name.toUpperCase() $: console.log({ name }) </script> <h1>Hello {name}!</h1> <button on:click={flip}>flip!</button> `