打包器

.
├── index.tsx
├── Component.tsx
└── out
    └── index.js

// out/index.js
// ...
// 约 2 万行代码
// 包含了 `react-dom/client` 及所有依赖的内容
// 这里定义了 $jsxDEV 和 $createRoot 函数

// Component.tsx
function Component(props) {
  return $jsxDEV(
    "p",
    {
      children: props.message,
    },
    undefined,
    false,
    undefined,
    this,
  );
}

// index.tsx
var rootNode = document.getElementById("root");
var root = $createRoot(rootNode);
root.render(
  $jsxDEV(
    Component,
    {
      message: "Sup!",
    },
    undefined,
    false,
    undefined,
    this,
  ),
);

bun build ./index.tsx --outdir ./out --watch

const result = await Bun.build({
  entrypoints: ["./index.ts"],
});

for (const res of result.outputs) {
  // 可作为 Blob 处理
  await res.text();

  // Bun 会自动设置 Content-Type 和 Etag 头
  new Response(res);

  // 也可手动写入，但此时推荐使用 `outdir` 选项。
  Bun.write(path.join("out", res.path), res);
}

.
├── entry-a.tsx
├── entry-b.tsx
├── shared.tsx
└── out
    ├── entry-a.js
    ├── entry-b.js
    └── chunk-2fce6291bf86559d.js

await Bun.build({
  entrypoints: ["./index.tsx"],
  outdir: "./out",
  plugins: [
    /* ... */
  ],
});

// input.js
console.log(process.env.FOO);
console.log(process.env.BAZ);

// output.js
console.log("bar");
console.log("123");

FOO=bar BAZ=123 ACME_PUBLIC_URL=https://acme.com

console.log(process.env.FOO);
console.log(process.env.ACME_PUBLIC_URL);
console.log(process.env.BAZ);

console.log(process.env.FOO);
console.log("https://acme.com");
console.log(process.env.BAZ);

import _ from "lodash";
import { z } from "zod";

const value = z.string().parse("Hello world!");
console.log(_.upperCase(value));

import { z } from "zod";

// ...
// lodash 源码
// 包括 `_.upperCase` 函数

var value = z.string().parse("Hello world!");
console.log(_.upperCase(value));

.
├── index.tsx
└── out
    └── index.js

.
├── index.tsx
└── nested
    └── index.tsx
└── out
    ├── index.js
    └── nested
        └── index.js

.
├── index.tsx
└── out
    └── files
        └── index-a1b2c3d4.js

.
└── pages
  └── index.tsx
  └── settings.tsx

.
└── pages
  └── index.tsx
  └── settings.tsx
└── out
  └── index.js
  └── settings.js

var logo = "https://cdn.example.com/logo-a7305bdef.svg";

import { feature } from "bun:bundle";

if (feature("PREMIUM")) {
  // 仅 PREMIUM 标记启用时包含
  initPremiumFeatures();
}

if (feature("DEBUG")) {
  // 仅 DEBUG 标记启用时包含
  console.log("Debug mode");
}

import { feature } from "bun:bundle";
const mode = feature("PREMIUM") ? "premium" : "free";

var mode = "premium";

var mode = "free";

declare module "bun:bundle" {
  interface Registry {
    features: "DEBUG" | "PREMIUM" | "BETA_FEATURES";
  }
}

interface BuildOutput {
  outputs: BuildArtifact[];
  success: boolean;
  logs: Array<object>; // 详见文档
}

interface BuildArtifact extends Blob {
  kind: "entry-point" | "chunk" | "asset" | "sourcemap";
  path: string;
  loader: Loader;
  hash: string | null;
  sourcemap: BuildArtifact | null;
}

const build = await Bun.build({
  /* */
});

for (const output of build.outputs) {
  await output.arrayBuffer(); // => ArrayBuffer
  await output.bytes(); // => Uint8Array
  await output.text(); // string
}

const build = await Bun.build({
  /* */
});

const artifact = build.outputs[0];

// 会自动设置 Content-Type 头
return new Response(artifact);

bun build ./cli.tsx --outfile mycli --compile
./mycli

try {
  const result = await Bun.build({
    entrypoints: ["./index.tsx"],
    outdir: "./out",
  });
} catch (e) {
  // TS 不允许在 catch 加类型注解，故用断言
  const error = e as AggregateError;
  console.error("构建失败");

  // 示例：内置格式化打印
  console.error(error);

  // 示例：序列化成 JSON 字符串打印
  console.error(JSON.stringify(error, null, 2));
}

class BuildMessage {
  name: string;
  position?: Position;
  message: string;
  level: "error" | "warning" | "info" | "debug" | "verbose";
}

class ResolveMessage extends BuildMessage {
  code: string;
  referrer: string;
  specifier: string;
  importKind: ImportKind;
}

const result = await Bun.build({
  entrypoints: ["./index.tsx"],
  outdir: "./out",
});

if (result.logs.length > 0) {
  console.warn("构建成功但有警告：");
  for (const message of result.logs) {
    // Bun 将美化打印信息
    console.warn(message);
  }
}