What is custom formatting?

You can use custom formatting for some of the formatting cases such as ICU formatting syntax (message "pattern" strings with variable-element placeholders enclosed in {curly braces}). It implement Formatter Interface.

// Custom Formatter implementation
class CustomFormatter {
constructor (options) {
// ...
}
interpolate (message, values) {
// return the interpolated array
return ['resolved message string']
}
}

// register with `formatter` option
const i18n = new VueI18n({
locale: 'en-US',
formatter: new CustomFormatter(/* here the constructor options */),
messages: {
'en-US': {
// ...
},
// ...
}
})

// Run!
new Vue({ i18n }).$mount('#app')