VueJs calling :key in method - vuejs3

Question

im new to Vue and trying myself in Vue3 and Vuetify.
Similar to this Post im trying to :key or ref a vue-signature-pad in a for loop.
I initialize an empty Array and push a new element, which adds a new signature.
<template>
<div>
<v-container>
<div class="row" v-for="(input, index) in inputs">
<v-container>
<VueSignaturePad
id="signature"
width="100%"
height="300px"
ref="signaturePad"
/>
</v-container>
<div class="buttons">
<button #click="undo">Undo</button>
<button #click="save">Save</button>
</div>
</div>
<v-row justify="center">
<v-btn #click="addRow"
class="ma-2"
color="blue-grey"
icon="mdi-plus-circle-outline"
></v-btn>
</v-row>
</v-container>
</div>
</template>
<script>
export default {
data: () => ({
inputs: [],
}),
methods: {
addRow() {
this.inputs.push({
name: ''
})
},
undo() {
this.$refs.signaturePad.undoSignature();
},
save() {
const { isEmpty, data } = this.$refs.signaturePad.saveSignature();
alert("Open DevTools see the save data.");
console.log(isEmpty);
console.log(data);
}
}
}
</script>
<style scope>
</style>
In the Post i already mentioned, i tried the Solution from Mathieu Janio.
So if i understand everything right, ref is not working and i have to use :key on the div itself.
So i tried his Solution
<template>
<div
class="row"
v-for="(applicants, index) in applicant_details"
:key="index"
>
<div class="col-sm-4">
<div class="form-group">
<p>Signature for {{ applicants.first_name }}</p>
</div>
</div>
<div class="col-sm-4">
<div class="form-group">
<VueSignaturePad ref="" />
<button type="button" #click="undo" class="btn btn-warning">
Undo
</button>
</div>
</div>
</div>
</template>
<script setup>
const applicant_details = [
{ first_name: 'john', signature: '' },
];
const undo = () => {
//will undo the signature
};
const save_signature = () => {
//Save the signature
};
</script>
But now im stuck at calling the right "undo"
The signatepad github example uses ref: at the single signaturepad, which is ok.
but not working at the forloop
How do i call now the right function in "undo" for the solution above?
I tried using "this.$.vnode.key" but this gives me an error.
"Uncaught TypeError: Cannot read properties of undefined (reading '$')".

Answer 1

I figured my first way out.
Heres what i have done.
The Signaturepad got an index on the ref.
<VueSignaturePad
:id="'signaturePad' + index"
width="100%"
height="300px"
:ref="'signaturePad' + index"
:options="options"
/>
The "undo" button is giving it "ref" with
<button #click="undo(`signaturePad${index}`)">Undo</button>
And the undo function itself has the first item in its ref array
undo(ref) {
this.$refs[ref][0].undoSignature();
}
Maybe someone has some more efficient way. Feel free :)