Validate Plugin Configuration

Each plugin can also provide a function to validate the configuration before executing it.

You can use this function to:

• test for other plugin’s existence (for example, if your plugin requires another plugin to function correctly)
• validate the name and path of the output file
• validate the schema or documents

And much more!

To add your plugin validation method, export a function called validate from your plugin file:

module.exports = {
  plugin(schema, documents, config, info) {
    const typesMap = schema.getTypeMap()

    return Object.keys(typesMap).join('\n')
  },
  validate(schema, documents, config, outputFile, allPlugins) {}
}

You can now check the schema, documents, configuration, output file and sibling plugins, and in case something does not fits your requirements, throw an Error:

module.exports = {
  plugin(schema, documents, config, info) {
    const typesMap = schema.getTypeMap()

    return Object.keys(typesMap).join('\n')
  },
  validate(schema, documents, config, outputFile, allPlugins) {
    if (!config.mustHave) {
      throw new Error(`You must specify "mustHave" in my plugin configuration!`)
    }
  }
}