Create babel plugin to handle lazy loading (#4)

* feat: create babel plugin to handle lazy loading

* fix: update typescript CI to also run the tests in the pipelines

* doc: update lazy loading component inline documentation

* fix: typescript pipeline

* fix: update CI typescript test command

* fix: prevent duplicate pipelines on PR

* feat: create separate vite plugin package

* chore: refined lazy fn package

* test: add test to lazy fn plugin

* feat: update version to v0.1.5

packages/lazy-fn-vite-plugin/.prettierignore

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+dist
+pnpm-lock.yaml

packages/lazy-fn-vite-plugin/README.md

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+# tuono-lazy-fn-vite-plugin

packages/lazy-fn-vite-plugin/package.json

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+{
+  "name": "tuono-lazy-fn-vite-plugin",
+  "version": "0.1.5",
+  "description": "Plugin for the tuono's lazy fn. Tuono is the react/rust fullstack framework",
+  "scripts": {
+    "dev": "vite build --watch",
+    "build": "vite build",
+    "lint": "eslint --ext .ts,.tsx ./src -c ../../.eslintrc",
+    "format": "prettier -u --write --ignore-unknown '**/*'",
+    "format:check": "prettier --check --ignore-unknown '**/*'",
+    "types": "tsc --noEmit",
+    "test": "vitest run"
+  },
+  "keywords": [],
+  "author": "Valerio Ageno",
+  "license": "MIT",
+  "type": "module",
+  "types": "dist/esm/index.d.ts",
+  "main": "dist/cjs/index.cjs",
+  "module": "dist/esm/index.js",
+  "files": [
+    "dist",
+    "src",
+    "README.md"
+  ],
+  "exports": {
+    ".": {
+      "import": {
+        "types": "./dist/esm/index.d.ts",
+        "default": "./dist/esm/index.js"
+      },
+      "require": {
+        "types": "./dist/cjs/index.d.cts",
+        "default": "./dist/cjs/index.cjs"
+      }
+    },
+    "./package.json": "./package.json"
+  },
+  "dependencies": {
+    "@babel/core": "^7.24.4",
+    "@babel/types": "^7.24.0",
+    "vite": "^5.2.11"
+  },
+  "devDependencies": {
+    "@tanstack/config": "^0.7.11",
+    "@types/babel__core": "^7.20.5",
+    "prettier": "^3.2.4",
+    "vitest": "^1.5.2"
+  }
+}

packages/lazy-fn-vite-plugin/src/index.ts

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+import type { Plugin } from 'vite'
+import * as babel from '@babel/core'
+import type { PluginItem } from '@babel/core'
+
+import * as t from '@babel/types'
+
+import type {
+  Identifier,
+  ImportDeclaration,
+  CallExpression,
+  ArrowFunctionExpression,
+  StringLiteral,
+} from '@babel/types'
+
+/**
+ * This plugin just removes the `lazy` imported function from any tuono import
+ */
+const RemoveTuonoLazyImport: PluginItem = {
+  name: 'remove-tuono-lazy-import-plugin',
+  visitor: {
+    ImportSpecifier: (path) => {
+      if ((path.node.imported as Identifier).name === 'lazy') {
+        if (
+          (path.parentPath.node as ImportDeclaration).source.value === 'tuono'
+        ) {
+          path.remove()
+        }
+      }
+    },
+  },
+}
+
+/**
+ * Import { lazy } from 'react'
+ */
+const ImportReactLazy: PluginItem = {
+  name: 'import-react-lazy-plugin',
+  visitor: {
+    Program: (path: any) => {
+      let isReactImported = false
+
+      path.node.body.forEach((val: any) => {
+        if (val.type === 'ImportDeclaration' && val.source.value === 'react') {
+          isReactImported = true
+          // TODO: Handle also here case of already imported react
+          // Right now works just for the main routes file
+        }
+      })
+
+      // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+      if (!isReactImported) {
+        const importDeclaration = t.importDeclaration(
+          [t.importSpecifier(t.identifier('lazy'), t.identifier('lazy'))],
+          t.stringLiteral('react'),
+        )
+        path.unshiftContainer('body', importDeclaration)
+      }
+    },
+  },
+}
+
+/**
+ * For the server side we need to statically import the lazy loaded components
+ */
+const TurnLazyToStaticImport: PluginItem = {
+  name: 'turn-lazy-to-static-import-plugin',
+  visitor: {
+    VariableDeclaration: (path) => {
+      path.node.declarations.forEach((el) => {
+        const init = el.init as CallExpression
+        if ((init.callee as Identifier).name === 'lazy') {
+          const importName = (el.id as Identifier).name
+          const importPath = (
+            (
+              (init.arguments[0] as ArrowFunctionExpression)
+                .body as CallExpression
+            ).arguments[0] as StringLiteral
+          ).value
+
+          if (importName && importPath) {
+            const importDeclaration = t.importDeclaration(
+              [t.importDefaultSpecifier(t.identifier(importName))],
+              t.stringLiteral(importPath),
+            )
+
+            path.replaceWith(importDeclaration)
+          }
+        }
+      })
+    },
+  },
+}
+
+export function LazyLoadingPlugin(): Plugin {
+  return {
+    name: 'vite-plugin-tuono-lazy-loading',
+    enforce: 'pre',
+    transform(code, _id, opts): string | undefined | null {
+      if (code.includes('lazy') && code.includes('tuono')) {
+        const res = babel.transformSync(code, {
+          plugins: [
+            ['@babel/plugin-syntax-jsx', {}],
+            ['@babel/plugin-syntax-typescript', { isTSX: true }],
+            [RemoveTuonoLazyImport],
+            [!opts?.ssr ? ImportReactLazy : []],
+            [opts?.ssr ? TurnLazyToStaticImport : []],
+          ],
+          sourceMaps: true,
+        })
+
+        return res?.code
+      }
+      return code
+    },
+  }
+}

packages/lazy-fn-vite-plugin/test/transpileSource.test.ts

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+import { it, expect, describe } from 'vitest'
+import { LazyLoadingPlugin } from '../src'
+
+const SOURCE_CODE = `
+import { createRoute, lazy } from 'tuono'
+
+const IndexImport = lazy(() => import('./../src/routes/index'))
+const PokemonspokemonImport = lazy(
+  () => import('./../src/routes/pokemons/[pokemon]'),
+)
+`
+
+const CLIENT_RESULT = `import { lazy } from "react";
+import { createRoute } from 'tuono';
+const IndexImport = lazy(() => import('./../src/routes/index'));
+const PokemonspokemonImport = lazy(() => import('./../src/routes/pokemons/[pokemon]'));`
+
+const SERVER_RESULT = `import { createRoute } from 'tuono';
+import IndexImport from "./../src/routes/index";
+import PokemonspokemonImport from "./../src/routes/pokemons/[pokemon]";`
+
+describe('Transpile tuono source', () => {
+  it('Into the client bundle', () => {
+    const bundle = LazyLoadingPlugin().transform?.(SOURCE_CODE, 'id')
+    expect(bundle).toBe(CLIENT_RESULT)
+  })
+
+  it('Into the server bundle', () => {
+    const bundle = LazyLoadingPlugin().transform?.(SOURCE_CODE, 'id', {
+      ssr: true,
+    })
+    expect(bundle).toBe(SERVER_RESULT)
+  })
+})

packages/lazy-fn-vite-plugin/tsconfig.json

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+{
+  "extends": "../../tsconfig.json",
+  "include": ["src", "vite.config.ts"]
+}

packages/lazy-fn-vite-plugin/vite.config.ts

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+import { defineConfig, mergeConfig } from 'vitest/config'
+import { tanstackBuildConfig } from '@tanstack/config/build'
+
+const config = defineConfig({})
+
+export default mergeConfig(
+  config,
+  tanstackBuildConfig({
+    entry: './src/index.ts',
+    srcDir: './src',
+  }),
+)