filters.md

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Filters

Overview

Filters are removed from Vue 3.0 and no longer supported.

2.x Syntax

In 2.x, developers could use filters in order to apply common text formatting.

For example:

<template>
  <h1>Bank Account Balance</h1>
  <p>{{ accountBalance | currencyUSD }}</p>
</template>

<script>
  export default {
    props: {
      accountBalance: {
        type: Number,
        required: true
      }
    },
    filters: {
      currencyUSD(value) {
        return '$' + value
      }
    }
  }
</script>

While this seems like a convenience, it requires a custom syntax that breaks the assumption of expressions inside curly braces being "just JavaScript," which has both learning and implementation costs.

3.x Update

In 3.x, filters are removed and no longer supported. Instead, we recommend replacing them with method calls or computed properties.

Using the example above, here is one example of how it could be implemented.

<template>
  <h1>Bank Account Balance</h1>
  <p>{{ accountInUSD }}</p>
</template>

<script>
  export default {
    props: {
      accountBalance: {
        type: Number,
        required: true
      }
    },
    computed: {
      accountInUSD() {
        return '$' + this.accountBalance
      }
    }
  }
</script>

Migration Strategy

Instead of using filters, we recommend replacing them with computed properties or methods.

Migration build flags:

• FILTERS
• COMPILER_FILTERS

Global Filters

If you are using filters that were globally registered and then used throughout your app, it's likely not convenient to replace them with computed properties or methods in each individual component.

Instead, you can make your global filters available to all components through globalProperties:

// main.js
const app = createApp(App)

app.config.globalProperties.$filters = {
  currencyUSD(value) {
    return '$' + value
  }
}

Then you can fix all templates using this $filters object like this:

<template>
  <h1>Bank Account Balance</h1>
  <p>{{ $filters.currencyUSD(accountBalance) }}</p>
</template>

Note that with this approach, you can only use methods, not computed properties, as the latter only make sense when defined in the context of an individual component.