Entities

Entities are the heart of Nevr. They define shape, validation, relations, and authorization defaults.

Define an Entity

import { entity, string, text, bool } from "nevr"

export const post = entity("post", {
  title: string.min(1).max(200),
  body: text,
  published: bool.default(false),
})

Field Types & Modifiers

Available field types:

• string, text, int, float, boolean (alias: bool), datetime, json, email

Common modifiers:

• .optional() mark as nullable
• .unique() unique constraint (reflected in schema)
• .default(value) default on create
• .min(n) / .max(n) length/value constraints

Examples:

import { entity, string, int, email } from "nevr"

export const user = entity("user", {
  email: email.unique(),
  name: string.min(1).max(100),
  age: int.min(0).optional(),
})

Relations

Nevr supports three relation builders:

• belongsTo(() => Target) — many-to-one, adds a foreign key (default: <field>Id)
• hasMany(() => Target) — one-to-many (inverse collection)
• hasOne(() => Target) — one-to-one (unique)

Options:

• .foreignKey("customId")
• .onDelete("cascade" | "setNull" | "restrict")
• .optional()

import { entity, string, belongsTo, hasMany } from "nevr"

export const user = entity("user", { name: string })

export const project = entity("project", {
  name: string,
  owner: belongsTo(() => user).onDelete("cascade"),
})

export const task = entity("task", {
  title: string,
  project: belongsTo(() => project),
  assignee: belongsTo(() => user),
})

When there are multiple belongsTo to the same target, Prisma relation names are generated automatically.

Authorization Defaults with ownedBy

ownedBy(field) sets sensible CRUD rules based on ownership:

export const post = entity("post", { author: belongsTo(() => user) })
  .ownedBy("author")

Shorthand for:

.rules({
  create: ["authenticated"],
  read: ["everyone"],
  list: ["everyone"],
  update: ["owner"],
  delete: ["owner"],
})

Override with .rules() if needed.

Timestamps

Entities include createdAt/updatedAt by default. Disable with:

entity("audit", { /* ... */ }).noTimestamps()

Validation & Input

Input is validated from field definitions. Unknown fields are ignored to prevent mass assignment. For create, required fields are enforced unless a default exists.