Tag

tag is the simplest model in the app — a lightweight label (name + color) used to classify products. It has no relations of its own, but products hold a tags relation to it, so the tag gets a products back-reference injected by the relation engine.

// models/tag.ts (definition, trimmed of the doc comment)
import { coreApp } from "../mod.ts";
import { string } from "lesan";
import { createUpdateAt } from "@lib";

export const tag_pure = {
  name: string(),
  color: string(),
  ...createUpdateAt,
};

export const tag_relations = {};

export const tags = () =>
  coreApp.odm.newModel("tag", tag_pure, tag_relations, {
    createIndex: {
      indexSpec: { name: 1 },
      options: { unique: true },
    },
  });

Pure fields

Field	Type	Notes
name	string()	tag text; indexed unique
color	string()	hex code, e.g. #ff5252
createdAt / updatedAt	spread from createUpdateAt

Relations

tag_relations is empty. Even so, product.tags declares a back-reference (tag.products), so the model registry still gives tags an implicit products list — populated automatically whenever a product adds the tag.

Factory

export const tags = () =>
  coreApp.odm.newModel("tag", tag_pure, tag_relations, {
    createIndex: {
      indexSpec: { name: 1 },
      options: { unique: true },
    },
  });

The unique name index means you can't create Medical twice — the tag acts as an enforced enum by data.

In the workflow

• add-tag, get-tags
• update-tag, remove-tag

Products attach tags via updateProductRelations — see the product model.

Run it

curl -X POST http://localhost:1380/lesan \
  -H "Content-Type: application/json" \
  -H "token: <jwt>" \
  -d '{
    "service": "main",
    "model": "tag",
    "act": "getTags",
    "details": { "set": { "page": 1 }, "get": { "name": true, "color": true } }
  }'

Errors & fixes

Error	Cause	Fix
E11000 duplicate key error collection: advancedTutorial.tags	a tag with this name already exists	reuse the existing tag, or use a different name
tag not found	updateTag/removeTag given an unknown _id	use a real tag _id

note

Runtime On npm/Bun import the framework from @hemedani/lesan; on Deno from jsr:@hemedani/lesan. The repo app itself uses the lesan path alias.