In the `jsonapi-serializer` library for serializing JSON API data, you can customize how relationships are represented, including returning the slug instead of the id for a relationship. You can achieve this by using the `keyForAttribute` and `relationshipLinks` options when defining your serializer.
Here's how you can return a slug instead of an id for a relationship using `jsonapi-serializer`:
Assuming you have a model with a relationship like this:
```javascript
// Model
{
id: 1,
name: "Example Model",
slug: "example-model"
}
```
1. Define your serializer and specify how relationships should be serialized:
```javascript
const JSONAPISerializer = require("jsonapi-serializer").Serializer;
const serializer = new JSONAPISerializer("model", {
attributes: ["name", "slug"], // Include the attributes you want
keyForAttribute: "underscored", // You can customize the key format
relationshipLinks: {
// Customize the relationship links
slug: (data) => `/models/${data.slug}`,
},
});
```
2. Use the serializer to serialize your data:
```javascript
const data = {
id: 1,
name: "Example Model",
slug: "example-model",
};
const serializedData = serializer.serialize(data);
console.log(serializedData);
```
The output will now have a "slug" attribute in the "model" relationship, and the links will be customized to use the slug:
```json
{
"data": {
"id": "1",
"type": "model",
"attributes": {
"name": "Example Model",
"slug": "example-model"
},
"relationships": {
"slug": {
"data": {
"type": "model",
"id": "example-model"
},
"links": {
"self": "/models/example-model"
}
}
}
}
}
```
By customizing the `relationshipLinks` option, you can control the links for the relationship and return the slug instead of the id.