loopback4-slug/src/repositories/slug.repository.ts

Slug generator for LoopBack 4

import {MetadataInspector, MixinTarget} from '@loopback/core';
import {Entity, EntityCrudRepository, PropertyMap} from '@loopback/repository';
import slugify from 'slugify';
import {PropertyDefinition} from '../types';
import {MODEL_SLUG_KEY} from '../keys';
import debugFactory from 'debug';

export const debug = debugFactory('loopback:slug');

/* eslint-disable @typescript-eslint/ban-ts-comment */
export function SlugRepositoryMixin<T extends Entity, Relations extends object>() {
  return function <R extends MixinTarget<EntityCrudRepository<T, string, Relations>>>(superClass: R) {
    class SlugRepository extends superClass {
      definePersistedModel(entityClass: typeof Entity) {
        debug('Execute method "definePersistedModel()"');
        // @ts-ignore
        const modelClass = super.definePersistedModel(entityClass);
        // @ts-ignore
        modelClass.observe('before save', async ctx => {
          if (ctx.instance) {
            debug('Run "before save" script');
            const propertyMap: PropertyMap =
              MetadataInspector.getAllPropertyMetadata<PropertyDefinition>(MODEL_SLUG_KEY, entityClass.prototype) ?? {};
            for (const [propName, propDef] of Object.entries(propertyMap)) {
              debug('Generate slug from field "%s" to field "%s"', propDef.field, propName);
              ctx.instance[propName] = slugify(ctx.instance[propDef.field], propDef.options);
            }
          }
        })
        return modelClass
      }
    }

    return SlugRepository
  }
}