complex-loader

complex-loader

Combine results from multiple loaders into one object.

{
  test: /\.md$/,
  exclude: /node_modules/,
  use: {
    loader : `complex-loader`,
    options: {
      attributes: [
        `json-loader`,
        `yaml-loader`,
        {
          loader : `front-matter-loader`,
          options: {
            onlyAttributes: true,
          },
        },
      ],
      Component: [
        {
          loader : `markdown-feat-react-loader`,
          options: {
            config: require.resolve(`./react-markdown.config.js`),
            importImages: true,
          }
        },
        {
          loader : `front-matter-loader`,
          options: {
            onlyBody: true,
          },
        },
      ]
    },
  }
}

Import all desired data about file by one import.

import readme from 'readme.md'

console.log(readme)
/*
{
  attributes: {...},
  Component: function()
}
*/

Motivation

There is another similar loader called combine-loader. But it allows you to specify loaders only in a string format. The reason for creating complex-loader was the support of defining loaders using javascript objects. This means that you can use functions, arrays, objects, and any others javascript entities.

Distant resources

If you are importing a resource from the outside the directory where node_modules have placed, specify loaders absolute paths by using require.resolve.

[
  require.resolve(`json-loader`),
  require.resolve(`yaml-loader`)
]

This is because, on the nested level, the paths to the loaders will be resolved relative to the directory in which your file is located.

Self-nesting

You can specify as nested loader the same complex-loader.

{
  test: /\.png/,
  exclude: /node_modules/,
  use: {
    loader : `complex-loader`,
    options: {
      deeper: {
        loader: `complex-loader`,
        options: {
          and: {
            loader: `complex-loader`,
            options: {
              deeper: 'url-loader'
            }
          }
        }
      }
    }
  }
}
// Will give:
/*
{
  deeper: {
    and: {
      deeper: 'path/to/file.png'
    }
  }
}
*/

Author and license

Vladimir Kalmykov [e-mail]

Under MIT license, 2018

See also

• invoke-loader Resolve and invoke loader and options, the paths to which are specified in the options
• git-commits-loader Collect information about file commits
• markdown-heading-loader Just get primary heading of markdown document
• markdown-feat-react-loader Use React components directly in markdown