Component Interpolation #

Basic Usage #

Sometimes, we need to localize with a locale message that was included in a HTML tag or component. For example:

<p>I accept xxx <a href="/term">Terms of Service Agreement</a></p>

In the above message, if you use $t, you will probably try to compose the following locale messages:

const messages = {
  en: {
    term1: 'I Accept xxx\'s',
    term2: 'Terms of Service Agreement'
  }
}

And your localized template may look like this:

<p>{{ $t('term1') }}<a href="/term">{{ $t('term2') }}</a></p>

Output:

<p>I accept xxx <a href="/term">Terms of Service Agreement</a></p>

This is very cumbersome, and if you configure the <a> tag in a locale message, there is a possibility of XSS vulnerabilities due to localizing with v-html="$t('term')".

You can avoid it using the Translation component (i18n-t). For example the below.

Template:

<div id="app">
  <!-- ... -->
  <i18n-t keypath="term" tag="label" for="tos">
    <a :href="url" target="_blank">{{ $t('tos') }}</a>
  </i18n-t>
  <!-- ... -->
</div>

JavaScript:

import { createApp } from 'vue'
import { createI18n } from 'vue-i18n'

const i18n = createI18n({
  locale: 'en',
  messages: {
    en: {
      tos: 'Term of Service',
      term: 'I accept xxx {0}.'
    },
    ja: {
      tos: '利用規約',
      term: '私は xxx の{0}に同意します。'
    }
  }
})

const app = createApp({
  data: () => ({ url: '/term' })
})

app.use(i18n)
app.mount('#app')

The following output:

<div id="app">
  <!-- ... -->
  <label for="tos">
    I accept xxx <a href="/term" target="_blank">Term of Service</a>.
  </label>
  <!-- ... -->
</div>

About the above example, see the example

The children of translation component are interpolated with locale message of keypath prop. In the above example,

Is interpolated with term locale message.

In the above example, the component interpolation follows the list interpolation. The children of translation component are interpolated by their order of appearance.

You can choose the root node element type by specifying a tag prop. If omitted, it defaults to Fragments.

Slots syntax usage #

It’s more convenient to use the named slots syntax. For example the below:

Template:

<div id="app">
  <!-- ... -->
  <i18n-t keypath="info" tag="p">
    <template v-slot:limit>
      <span>{{ changeLimit }}</span>
    </template>
    <template v-slot:action>
      <a :href="changeUrl">{{ $t('change') }}</a>
    </template>
  </i18n-t>
  <!-- ... -->
</div>

JavaScript:

import { createApp } from 'vue'
import { createI18n } from 'vue-i18n'

const i18n = createI18n({
  locale: 'en',
  messages: {
    en: {
      info: 'You can {action} until {limit} minutes from departure.',
      change: 'change your flight',
      refund: 'refund the ticket'
    }
  }
})

const app = createApp({
  data: () => ({
    changeUrl: '/change',
    refundUrl: '/refund',
    changeLimit: 15,
    refundLimit: 30
  })
})

app.use(i18n)
app.mount('#app')

Outputs:

<div id="app">
  <!-- ... -->
  <p>
    You can <a href="/change">change your flight</a> until <span>15</span> minutes from departure.
  </p>
  <!-- ... -->
</div>

You can also use the following slots shorthand in templates:

<div id="app">
  <!-- ... -->
  <i18n-t keypath="info" tag="p">
    <template #limit>
      <span>{{ changeLimit }}</span>
    </template>
    <template #action>
      <a :href="changeUrl">{{ $t('change') }}</a>
    </template>
  </i18n-t>
  <!-- ... -->
</div>

Pluralization Usage #

You can use pluralization in Component interpolation by use plural prop. For example the below.

Template:

<div id="app">
  <!-- ... -->
  <i18n-t keypath="message.plural" locale="en" :plural="count">
    <template #n>
      <b>{{ count }}</b>
    </template>
  </i18n-t>
  <!-- ... -->
</div>

JavaScript:

const { createApp, ref } = Vue
const { createI18n } = VueI18n

const i18n = createI18n({
  legacy: false,
  locale: 'en',
  messages: {
    en: {
      message: {
        plural: 'no bananas | {n} banana | {n} bananas'
      }
    }
  }
})

const app = createApp({
  setup() {
    const count = ref(2)
    return { count }
  }
})
app.use(i18n)
app.mount('#app')

The following output:

<div id="app" data-v-app="">
  <!-- ... -->
  <b>2</b> bananas
  <!-- ... -->
</div>

Scope resolving #

The Scope resolving of Translation component is parent as default.

It means that Translation component uses the scope that is enabled in the parent component that uses it.

If the parent component has useI18n in useScope: 'global', it will use Global Scope, else if useScope: 'local', it will use the Local Scope of the parent component.

However, You sometimes meet the warning message on your browser console the following:

[intlify] Not found parent scope. use the global scope.

This message is displayed in the case that you have not run useI18n in the parent component that uses the Translation component.

In that situation, the Scope of the Translation Component will be fallback to the global scope as said the warning message.

A workaround to suppress this warning is to specify global as the scope property of Translation component.

<i18n-t keypath="message.foo" scope="global">
  ...
</i18n-t>