如何从另一个组件调用function到另一个组件

Question

Now I'm confused how to fire function from component to control something in another component. Can anyone help me on this?

Structure:
App.svelte
L checklist.svelte
  L button <-- this button want to call function in stage component
L stage.svelte

checklist.svelte:
<button on:click="handleMove" />

stage.svelte:
export function fly(x, y) {
   $map.flyto(x, y);
}

I have a button in checklist component that want to activate function that in stage component.

Stage component is a map that have xy position and function that move things inside this component.

How can I call function in stage component from the outside (checklist components)?

Answer 1

You have a couple of options:

first and the most flexible one is to create a writable store to use it anywhere

second it to use context

third is to declare it in App.svelte and bind it to both children

Answer 2

You could do the following:

1. Dispatch a custom checklist-click event from Checklist.
2. In App, listen to this click event and call fly on Stage.

<!-- App.svelte -->
<script>
    import Checklist from './Checklist.svelte';
    import Stage from './Stage.svelte';
    
    let stage;
    
    function handleClick({ detail }) {
        // these come from the second argument to dispatch in Checklist.svelte
        const { x, y } = detail;
        stage.fly(x, y);
    }
</script>

<h1>App</h1>

<!-- Listen to the event fired with dispatch('checklist-click') -->
<Checklist on:checklist-click={handleClick}></Checklist>

<!-- Store a reference to this component instance so that we can call `fly` on it -->
<Stage bind:this={stage}></Stage>

<!-- Checklist.svelte -->
<script>
    import { createEventDispatcher } from 'svelte';
    const dispatch = createEventDispatcher();
    
    function handleMove() {
        dispatch('checklist-click', {x: 5, y: 10});
    }
</script>

<h2>Checklist</h2>

<button on:click={handleMove}>
    Move
</button>

<!-- Stage.svelte -->
<script>
    export function fly(x, y) {
        console.log(`fly called from stage with x: ${x}, y: ${y}`);
    }
</script>


<h2>Stage</h2>

For more on dispatching component events, see the Svelte tutorial .