vite-plugin-use-build

This vite plugin help you to evaluate export values of esm module at build time, also allow you to import the values at runtime

Usage

use use build directive to declare a build time file, in following code snippet, fetchMessage and zod schema validation is done at build time

// env.ts
"use build"

import { z } from "zod"
import { envSchema } from "./env-schema"

async function fetchMessage() {
    console.log("should only run on build time")
    const delay = (ms: number) => new Promise(resolve => setTimeout(resolve, ms))
    await delay(1000)
    return "Hello world"
}

export const env = envSchema.parse(import.meta.env)

export const message = z.string().parse(await fetchMessage())

export default 123

and you can use all export values by directly importing the build time file at runtime

import { useState } from "react"
import { container } from "./index.css"
import { message } from "./env"

export function Main() {
    const [count, setCount] = useState(0)

    return (
        <div className={container}>
            <button onClick={() => setCount(count => count + 1)}>count: {count}</button>
            <p>{message}</p>
        </div>
    )
}

Setup

npm install -D vite-plugin-use-build

// vite.config.ts
import { defineConfig } from "vite"
import { buildTimePlugin } from "vite-plugin-use-build"
import react from "@vitejs/plugin-react"

// https://vitejs.dev/config/
export default defineConfig({
    plugins: [react(), buildTimePlugin()]
})

Caveat

All export values from build time file must be serializable.

Todo

• [ ] HMR

• [ ] Tests

• [ ] add support for .build.{ts,tsx,js,jsx} files

• [ ] allow other plugins to run at vite runtime

Inspirations

GitHub - t3-oss/t3-env

GitHub - egoist/vite-plugin-compile-time: Some compile-time magic for your Vite project

License

MIT.