Multitenancy Support

AshTypescript provides automatic tenant parameter handling for multitenant resources. This is commonly used in SaaS applications where each customer or organization needs isolated data access.

Overview

When a resource is configured with Ash multitenancy (using either :attribute or :context strategy), AshTypescript can automatically add tenant parameters to generated TypeScript function signatures, ensuring type-safe tenant isolation at compile time.

Configuration

The require_tenant_parameters setting controls how tenants are provided:

# config/config.exs
config :ash_typescript, require_tenant_parameters: true

When true (explicit tenants):

Tenant must be provided as a parameter in every RPC call
TypeScript enforces tenant parameter at compile time
Best for frontend applications that manage tenant context in state

When false (default - implicit tenants):

Tenant is extracted from the Phoenix connection (e.g., from session, JWT claims, or custom plug)
No tenant parameter in TypeScript function signatures

Explicit Tenant Parameters

With require_tenant_parameters: true, tenant parameters are automatically added to all RPC function signatures:

// Tenant parameter required in function signature
const projects = await listProjects({
  fields: ["id", "name", "status"],
  tenant: "acme-corp"  // Organization identifier
});

const invoice = await createInvoice({
  input: {
    customerId: "cust-456",
    amount: 1500
  },
  fields: ["id", "invoiceNumber"],
  tenant: "acme-corp"
});

Type Safety

When enabled, the tenant parameter is enforced at the TypeScript level:

// TypeScript enforces tenant parameter
const projects = await listProjects({
  fields: ["id", "name"]
  // ❌ TypeScript Error: Property 'tenant' is missing
});

const projects = await listProjects({
  fields: ["id", "name"],
  tenant: "acme-corp"  // ✅ Correct
});

How It Works

When you configure a resource with multitenancy in Ash (see the Ash Multitenancy Guide), AshTypescript automatically detects this and handles tenant parameters appropriately based on your configuration.

When calling RPC actions with require_tenant_parameters: true, the tenant value is passed to Ash and applied according to your resource's multitenancy strategy (:attribute or :context):

// Tenant is automatically applied by Ash based on your resource configuration
const projects = await listProjects({
  fields: ["id", "name"],
  tenant: "acme-corp"
});

Channel-based RPC

When using Phoenix channels, tenant parameters work identically to HTTP-based RPC:

import { listProjectsChannel } from './ash_rpc';
import { Channel } from "phoenix";

listProjectsChannel({
  channel: myChannel,
  fields: ["id", "name", "status"],
  tenant: "acme-corp",  // Tenant parameter required
  resultHandler: (result) => {
    if (result.success) {
      console.log("Projects:", result.data);
    }
  }
});

The tenant is included in the channel message payload and enforced server-side.