Howto do something when an attribute changes in svelte

问题

Creating a web component using svelte, I need to run some code when an attribute of the component is changed.

What I have come up with is the following pattern.

<script>
    export let test = "default value";

    $: {
        testIsChanged(test);
    }

    function testIsChanged(newValue) {
        console.log(newValue);
    }
</script>

The value of test is {test} 

Is this the way to do it? Or am I missing something?

回答1:

That will indeed work, as you can see in this REPL

来源：https://stackoverflow.com/questions/57976936/howto-do-something-when-an-attribute-changes-in-svelte