Vue Tip: Create Custom v-model Modifier

v-model has some built-in modifiers like .lazy, .number and .trim. But in some cases, you might need to add your own custom modifier.

In this simple demo, I want to create a custom modifier called no-underscore that removes all underscores _ from an input:

<Comp v-model.no-underscore="text" />

Inside our component we can access the modifier via the modelModifiers prop. We manipulate the value if an input event is fired and the modifier is available:

<script setup>
const props = defineProps({
  modelValue: String,
  modelModifiers: { default: () => ({}) },});

const emit = defineEmits(['update:modelValue']);

function emitValue(e) {
  let value = e.target.value;
  if (props.modelModifiers['no-underscore']) {    value = value.replace('_', '');
  }
  emit('update:modelValue', value);
}
</script>

<template>
  <input type="text" :value="modelValue" @input="emitValue" />
</template>

If your v-model binding includes both modifiers and argument then the generated prop name will be arg + "Modifiers":

<template>
  <Comp v-model:name.no-underscore="text" />
</template>

<script setup>
  const props = defineProps(['name', 'nameModifiers']);
  defineEmits(['update:name']);
</script>

Demo for this code is available at Vue SFC Playground

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