getPreloadCode() — vite Function Reference

Architecture documentation for the getPreloadCode() function in importAnalysisBuild.ts from the vite codebase.

Function typescript PluginSystem LegacySupport called by 1

Entity Profile

PluginSystem→ LegacySupport→ getPreloadCode() — vite Function Reference

Dependency Diagram

graph TD
  36e0844c_58c5_5f68_8102_cdd7d207e92c["getPreloadCode()"]
  04ad4685_2ce3_556a_152b_c93668a74b3b["importAnalysisBuild.ts"]
  36e0844c_58c5_5f68_8102_cdd7d207e92c -->|defined in| 04ad4685_2ce3_556a_152b_c93668a74b3b
  6d315957_5b5c_845c_10c4_b8cb46bc58eb["buildImportAnalysisPlugin()"]
  6d315957_5b5c_845c_10c4_b8cb46bc58eb -->|calls| 36e0844c_58c5_5f68_8102_cdd7d207e92c
  style 36e0844c_58c5_5f68_8102_cdd7d207e92c fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/vite/src/node/plugins/importAnalysisBuild.ts lines 165–195

function getPreloadCode(
  environment: PartialEnvironment,
  renderBuiltUrlBoolean: boolean,
  isRelativeBase: boolean,
) {
  const { modulePreload } = environment.config.build

  const scriptRel =
    modulePreload && modulePreload.polyfill
      ? `'modulepreload'`
      : `/* @__PURE__ */ (${detectScriptRel.toString()})()`

  // There are two different cases for the preload list format in __vitePreload
  //
  // __vitePreload(() => import(asyncChunk), [ ...deps... ])
  //
  // This is maintained to keep backwards compatibility as some users developed plugins
  // using regex over this list to workaround the fact that module preload wasn't
  // configurable.
  const assetsURL =
    renderBuiltUrlBoolean || isRelativeBase
      ? // If `experimental.renderBuiltUrl` is used, the dependencies might be relative to the current chunk.
        // If relative base is used, the dependencies are relative to the current chunk.
        // The importerUrl is passed as third parameter to __vitePreload in this case
        `function(dep, importerUrl) { return new URL(dep, importerUrl).href }`
      : // If the base isn't relative, then the deps are relative to the projects `outDir` and the base
        // is appended inside __vitePreload too.
        `function(dep) { return ${JSON.stringify(environment.config.base)}+dep }`
  const preloadCode = `const scriptRel = ${scriptRel};const assetsURL = ${assetsURL};const seen = {};export const ${preloadMethod} = ${preload.toString()}`
  return preloadCode
}