Sequelize paranoid delete cascade

models.js

import paranoidDeleteCascade from './helpers/paranoidDeleteCascade';

// Patch the paranoid delete functionality of Sequelize
sequelize.addHook('afterDestroy', paranoidDeleteCascade(db));

paranoid-delete-cascade.js

import isArray from 'lodash/isArray';
import map from 'lodash/map';

const paranoidDeleteCascade = (models) =>
  async (instance, options, next) => {
    // Only operate on paranoid models
    if (!instance.$modelOptions.paranoid) {
      return next();
    }

    const modelName = instance.$modelOptions.name.singular;

    await Promise.all(
      // Go over all associations of the instance model, and delete if needed
      map(models[modelName].associations, async (association) => {
        try {
          // Only delete if cascade is set up correctly
          if (association.options.onDelete !== 'CASCADE') {
            return true;
          }

          let relationModel = association.target;

          const getOptions = {};

          // Handle "through" cases
          if (association.through) {
            relationModel = association.through.model;

            // Include the id of the through model instance
            getOptions.include = [{
              model: relationModel,
            }];
          }

          // Load id(s) of association
          const instances = await instance[`get${association.as}`](getOptions);

          if (isArray(instances)) {
            // Association has no results so nothing to delete
            if (instances.length === 0) {
              return true;
            }

            // Delete all individually as bulk delete doesn't cascase in sequelize
            return await Promise.all(instances.map(i => i.destroy()));
          }

          // Association is not set, so nothing to delete
          if (!instances) {
            return true;
          }

          return await instances.destroy();
        } catch (error) {
          // If we had issues deleting, we have bigger problems
          Promise.resolve(true);
        }

        return true;
      })
    );

    return next();
  };

export default paranoidDeleteCascade;