component-mapping

name	component-mapping
description	Use when the user wants to create a vNext Mapping (sys-mappings) component — a reusable C# helper/code class (e.g. a crypto or JSON helper) that other components reference via scripts.helpers or encoding REF. Fetches mapping-definition.schema.json first, scaffolds the Mappings/{key}.json envelope + the .csx static class, and explains wiring it into consumers.

Component Mapping (sys-mappings)

A Mapping is a reusable C# class shared across components — a helper (RsaCryptoHelper, JsonHelper) or a whole reusable mapping (InitialTransMapping). Other components load it via a scripts.helpers reference, or reference a whole mapping with encoding: "REF". This avoids duplicating .csx logic across workflows/tasks/functions.

See references/concepts/mappings-and-scripts.md for the concept and references/concepts/csx-contracts.md for the C# side.

Prerequisites

• Working directory is a vNext domain project (vnext.config.json present).
• You know the helper's purpose and its C# class name.

Canonical schema-first (mandatory pre-step)

Before producing JSON, read mapping-definition.schema.json for the workspace's pinned schema (node_modules/@burgan-tech/vnext-schema/schemas/mapping-definition.schema.json; if node_modules is absent, npm install or fall back to references/concepts/mappings-and-scripts.md). Drive the envelope from the schema, never from memory.

Steps

1. Resolve paths from vnext.config.json

Capture paths.componentsRoot, paths.mappings (e.g. Mappings), domain. Target write path: {componentsRoot}/{paths.mappings}/{domain-subfolder}/{key}.json with the .csx under its src/.

2. Gather the mapping

• key (kebab-case, e.g. rsa-crypto) and the C# class name (name, PascalCase, e.g. RsaCryptoHelper).
• Kind: a helper (plain public static class with utility methods) or a reusable mapping (implements a mapping interface — see csx-contracts.md).
• External assemblies it needs (e.g. System.Security.Cryptography, Newtonsoft.Json) — consumers must list these in allowedAssemblies.

3. Scaffold the .csx

A helper is a plain static class (no IMapping):

using System.Security.Cryptography;
namespace Acme.Helpers;

public static class RsaCryptoHelper
{
    public static string Encrypt(string plain, string publicKeyBase64) { /* ... */ }
}

PascalCase class matching name; one class per file; kebab-case filename. Never hand-base64 code — the VS Code extension encodes the .csx into code on save.

4. Write the component JSON

{
  "key": "{key}", "version": "1.0.0", "domain": "{domain}",
  "flow": "sys-mappings", "flowVersion": "1.0.0", "tags": ["{tag}"],
  "attributes": {
    "name": "{ClassName}",
    "location": "./src/{ClassName}.csx",
    "code": "",
    "encoding": "NAT"   // sys-mappings supports B64 or NAT only — NEVER REF (it is the ref target)
  }
}

5. Wire it into consumers (explain to the user)

• Use a helper class: add a scripts block to the consumer's mapping (or workflow attributes.scripts):

  "scripts": {
    "helpers": [ { "key": "{key}", "version": "1.0.0", "domain": "{domain}", "flow": "sys-mappings" } ],
    "allowedAssemblies": [ "System.Security.Cryptography" ]
  }
  

  The helper's static class is then callable by name in the consumer's .csx.
• Reference a whole mapping: set the consumer mapping's encoding: "REF" and code to the mappingRef { key, version, domain, flow: "sys-mappings" }.

6. Validate

npm run validate. Hand failures to validate-and-fix.

Notes

• sys-mappings encoding is B64 or NAT only — it cannot be REF (no self-reference).
• Register in exports.mappings (vnext.config.json) only if shared cross-domain.
• The sandbox/security model for allowedAssemblies and helper runtime linking is documented on the vNext docs portal — fetch it if a consumer's script fails to resolve a helper or assembly.