create-react-app build后资源无法找到

CRA定义的PUBLIC_URL里面的源码：

const envPublicUrl = process.env.PUBLIC_URL;

const getPublicUrl = appPackageJson =>
  envPublicUrl || require(appPackageJson).homepage;

function getServedPath(appPackageJson) {
  const publicUrl = getPublicUrl(appPackageJson);
  const servedUrl =
    envPublicUrl || (publicUrl ? url.parse(publicUrl).pathname : '/');
  return ensureSlash(servedUrl, true);
}

默认会被替换为空 然后变为 / 目录

如果是生产环境 在package.json里面配置

"homepage": "."