mapSourcePosition() — vite Function Reference

Source Code

packages/vite/src/module-runner/sourcemap/interceptor.ts lines 173–235

function mapSourcePosition(position: OriginalMapping) {
  if (!position.source) return position
  let sourceMap = getRunnerSourceMap(position)
  if (!sourceMap) sourceMap = sourceMapCache[position.source]
  if (!sourceMap) {
    // Call the (overridable) retrieveSourceMap function to get the source map.
    const urlAndMap = retrieveSourceMap(position.source)
    if (urlAndMap && urlAndMap.map) {
      const url = urlAndMap.url
      sourceMap = sourceMapCache[position.source] = {
        url,
        map: new DecodedMap(
          typeof urlAndMap.map === 'string'
            ? JSON.parse(urlAndMap.map)
            : urlAndMap.map,
          url,
        ),
      }

      const contents = sourceMap.map?.map.sourcesContent
      // Load all sources stored inline with the source map into the file cache
      // to pretend like they are already loaded. They may not exist on disk.
      if (sourceMap.map && contents) {
        sourceMap.map.resolvedSources.forEach((source, i) => {
          const content = contents[i]
          if (content && source && url) {
            const contentUrl = supportRelativeURL(url, source)
            fileContentsCache[contentUrl] = content
          }
        })
      }
    } else {
      sourceMap = sourceMapCache[position.source] = {
        url: null,
        map: null,
      }
    }
  }

  // Resolve the source URL relative to the URL of the source map
  if (sourceMap.map && sourceMap.url) {
    const originalPosition = getOriginalPosition(sourceMap.map, position)

    // Only return the original position if a matching line was found. If no
    // matching line is found then we return position instead, which will cause
    // the stack trace to print the path and line for the compiled file. It is
    // better to give a precise location in the compiled file than a vague
    // location in the original file.
    if (originalPosition && originalPosition.source != null) {
      originalPosition.source = supportRelativeURL(
        sourceMap.url,
        originalPosition.source,
      )
      if (sourceMap.vite) {
        // @ts-expect-error vite is not defined
        originalPosition._vite = true
      }
      return originalPosition
    }
  }

  return position
}