improvement: JSON transform

[kazupon]

Current

• pass JSON string to vue-i18n

What to solve it?

• locale message merge performance

Points to be careful

• breaking change of JSON structure (string -> object)
• If JSON is huge, use JSON.parse hack
  • https://v8.dev/blog/cost-of-javascript-2019#json
  • webpack/webpack@14ee25c#diff-0b8a02ad0e17cc81bf776d636df37f6aR117-R119

[kazupon]

vue-i18n-loader@v2 or later, locale message & i18n custom block is pre-compiled