cache-loader

Caches the result of following loaders on disk (default) or in the database

Install

npm install --save-dev cache-loader

Usage

Add this loader in front of other (expensive) loaders to cache the result on disk.

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.ext$/,
        use: [
          'cache-loader',
          ...loaders
        ],
        include: path.resolve('src')
      }
    ]
  }
}

⚠️ Note that there is an overhead for saving the reading and saving the cache file, so only use this loader to cache expensive loaders.

Options

Name
Type
Default
Description
Name
cacheKey
Type
{Function(options, request) -> {String}}
Default
undefined
Description
Allows you to override default cache key generator
Name
cacheDirectory
Type
{String}
Default
path.resolve('.cache-loader')
Description
Provide a cache directory where cache items should be stored (used for default read/write implementation)
Name
cacheIdentifier
Type
{String}
Default
cache-loader:{version} {process.env.NODE_ENV}
Description
Provide an invalidation identifier which is used to generate the hashes. You can use it for extra dependencies of loaders (used for default read/write implementation)
Name
write
Type
{Function(cacheKey, data, callback) -> {void}}
Default
undefined
Description
Allows you to override default write cache data to file (e.g. Redis, memcached)
Name
read
Type
{Function(cacheKey, callback) -> {void}}
Default
undefined
Description
Allows you to override default read cache data from file

Examples

webpack.config.js

module.exports = {
  module: {
    rules: [
      {
        test: /\.js$/,
        use: [
          'cache-loader',
          'babel-loader'
        ],
        include: path.resolve('src')
      }
    ]
  }
}

##

webpack.config.js

// Or different database client - memcached, mongodb, ...
const redis = require('redis');
const crypto = require('crypto');

// ...
// connect to client
// ...

const BUILD_CACHE_TIMEOUT = 24 * 3600; // 1 day

function digest(str) {
  return crypto.createHash('md5').update(str).digest('hex');
}

// Generate own cache key
function cacheKey(options, request) {
  return `build:cache:${digest(request)}`;
}


// Read data from database and parse them
function read(key, callback) {
  client.get(key, (err, result) => {
    if (err) {
      return callback(err);
    }

    if (!result) {
      return callback(new Error(`Key ${key} not found`));
    }

    try {
      let data = JSON.parse(result);
      callback(null, data);
    } catch (e) {
      callback(e);
    }
  });
}


// Write data to database under cacheKey
function write(key, data, callback) {
  client.set(key, JSON.stringify(data), 'EX', BUILD_CACHE_TIMEOUT, callback);
}

module.exports = {
  module: {
    rules: [
      {
        test: /\.js$/,
        use: [
          {
            loader: 'cache-loader',
            options: {
              cacheKey,
              read,
              write,
            }
          },
          'babel-loader'
        ],
        include: path.resolve('src')
      }
    ]
  }
}

Maintainers


      Tobias Koppers


      Juho Vepsäläinen


      Joshua Wiens


      Michael Ciniawsky


      Alexander Krasnoyarov