loadPackageData() — vite Function Reference

Source Code

packages/vite/src/node/packages.ts lines 178–225

export function loadPackageData(pkgPath: string): PackageData {
  const data = JSON.parse(stripBomTag(fs.readFileSync(pkgPath, 'utf-8')))
  const pkgDir = normalizePath(path.dirname(pkgPath))
  const { sideEffects } = data
  let hasSideEffects: (id: string) => boolean | null
  if (typeof sideEffects === 'boolean') {
    hasSideEffects = () => sideEffects
  } else if (Array.isArray(sideEffects)) {
    if (sideEffects.length <= 0) {
      // createFilter always returns true if `includes` is an empty array
      // but here we want it to always return false
      hasSideEffects = () => false
    } else {
      const finalPackageSideEffects = sideEffects.map((sideEffect) => {
        /*
         * The array accepts simple glob patterns to the relevant files... Patterns like *.css, which do not include a /, will be treated like **\/*.css.
         * https://webpack.js.org/guides/tree-shaking/
         * https://github.com/vitejs/vite/pull/11807
         */
        if (sideEffect.includes('/')) {
          return sideEffect
        }
        return `**/${sideEffect}`
      })

      hasSideEffects = createFilter(finalPackageSideEffects, null, {
        resolve: pkgDir,
      })
    }
  } else {
    hasSideEffects = () => null
  }

  const resolvedCache: Record<string, string | undefined> = {}
  const pkg: PackageData = {
    dir: pkgDir,
    data,
    hasSideEffects,
    setResolvedCache(key, entry, options) {
      resolvedCache[getResolveCacheKey(key, options)] = entry
    },
    getResolvedCache(key, options) {
      return resolvedCache[getResolveCacheKey(key, options)]
    },
  }

  return pkg
}