Function applyHtmlTransforms

packages/vite/src/node/plugins/html.ts:1443–1494

(
  html: string,
  hooks: IndexHtmlTransformHook[],
  pluginContext: MinimalPluginContextWithoutEnvironment,
  ctx: IndexHtmlTransformContext,
)

}

export async function applyHtmlTransforms(
  html: string,
  hooks: IndexHtmlTransformHook[],
  pluginContext: MinimalPluginContextWithoutEnvironment,
  ctx: IndexHtmlTransformContext,
): Promise<string> {
  for (const hook of hooks) {
    const res = await hook.call(pluginContext, html, ctx)
    if (!res) {
      continue
    }
    if (typeof res === 'string') {
      html = res
    } else {
      let tags: HtmlTagDescriptor[]
      if (Array.isArray(res)) {
        tags = res
      } else {
        html = res.html || html
        tags = res.tags
      }

      let headTags: HtmlTagDescriptor[] | undefined
      let headPrependTags: HtmlTagDescriptor[] | undefined
      let bodyTags: HtmlTagDescriptor[] | undefined
      let bodyPrependTags: HtmlTagDescriptor[] | undefined

      for (const tag of tags) {
        switch (tag.injectTo) {
          case 'body':
            ;(bodyTags ??= []).push(tag)
            break
          case 'body-prepend':
            ;(bodyPrependTags ??= []).push(tag)
            break
          case 'head':
            ;(headTags ??= []).push(tag)
            break
          default:
            ;(headPrependTags ??= []).push(tag)
        }
      }
      headTagInsertCheck([...(headTags || []), ...(headPrependTags || [])], ctx)
      if (headPrependTags) html = injectToHead(html, headPrependTags, true)
      if (headTags) html = injectToHead(html, headTags)
      if (bodyPrependTags) html = injectToBody(html, bodyPrependTags, true)
      if (bodyTags) html = injectToBody(html, bodyTags)
    }
  }

  return html
}

const entirelyImportRE =
  /^(?:import\s*(?:"[^"\n]*[^\\\n]"|'[^'\n]*[^\\\n]');*|\/\*[\s\S]*?\*\/|\/\/.*[$\n])*$/