css-files-loader/src/utils.js

This loader is based on arshtepe's [css-file-loader](https://github.com/arshtepe/css-file-loader)

const fs = require("fs-extra");
const crypto = require('crypto');

module.exports.getFileHash = filePath => {
  return new Promise((resolve, reject) => {
    const read = fs.ReadStream(filePath);
    const hash = crypto.createHash('sha1');
    hash.setEncoding("hex");
    read.pipe(hash);
    read.on("end", () => {
      hash.end();
      resolve(hash.read());
    });
    read.on("error", reject);
  })
};

module.exports.getPublicPath = (compilation, options) => {
  if(options.publicPath) {
    return options.publicPath;
  }
  else if(compilation.outputOptions &&  compilation.outputOptions.publicPath) {
    return compilation.outputOptions.publicPath;
  }
  return "/";
};

module.exports.getOutputPath = (options) => {
  return typeof options.outputPath === "string" ? options.outputPath : "/";
};