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Configuard Configuard Configuard

Getting Started

Configuard turns a flat list of configuration rows — typically the contents of a config database table — into a nested, typed, immutable object your runtime can read safely.

Install

Section titled “Install”
Terminal window
npm i configuard

notation is a runtime dependency and is installed with it.

The Shape of a Row

Section titled “The Shape of a Row”

Each row is an IConfigItem — a key in dot/bracket notation, a raw string value, and the metadata that says how to parse it and who may see it. Here is a small device config used throughout these docs:

config rows
[
  {
    "accessor": "system",
    "appAccess": null,
    "key": "@UIColors",
    "type": "string",
    "listType": "csl",
    "value": "Blue,Red,Green,Amber",
    "options": null,
    "defaultValue": null,
    "editable": false,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Reusable list of allowed UI colors."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "company.name",
    "type": "string",
    "listType": "none",
    "value": "Acme",
    "options": null,
    "defaultValue": null,
    "editable": true,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Display name of the operator."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "device.port",
    "type": "integer",
    "listType": "none",
    "value": "8080",
    "options": null,
    "defaultValue": "8080",
    "editable": false,
    "requiresReboot": true,
    "encrypt": false,
    "description": "Port the device listens on. Reboot to apply."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "device.config.updateOnBoot",
    "type": "boolean",
    "listType": "none",
    "value": "true",
    "options": null,
    "defaultValue": "true",
    "editable": true,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Whether the device refreshes its config on boot."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "device.config.lifeSpan",
    "type": "integer",
    "listType": "none",
    "value": "1440",
    "options": null,
    "defaultValue": "1440",
    "editable": true,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Config validity window, in minutes."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "device.ui.accent",
    "type": "string",
    "listType": "none",
    "value": "Amber",
    "options": "${@UIColors}",
    "defaultValue": "Blue",
    "editable": true,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Accent color, constrained to the @UIColors list."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "device.protocol.transports",
    "type": "string",
    "listType": "array",
    "value": "http,mqtt",
    "options": null,
    "defaultValue": null,
    "editable": true,
    "requiresReboot": true,
    "encrypt": false,
    "description": "Enabled transports, parsed into a string array."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "environment.host",
    "type": "string",
    "listType": "none",
    "value": "device.local",
    "options": null,
    "defaultValue": null,
    "editable": true,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Base hostname for device endpoints."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "device.diagnostics.uploadUrl",
    "type": "string",
    "listType": "none",
    "value": "https://${environment.host}/upload",
    "options": null,
    "defaultValue": null,
    "editable": true,
    "requiresReboot": false,
    "encrypt": false,
    "description": "Diagnostics endpoint, templated off environment.host."
  },
  {
    "accessor": "system",
    "appAccess": null,
    "key": "db.password",
    "type": "string",
    "listType": "none",
    "value": "enc:5f3a9c2e7b104d8f",
    "options": null,
    "defaultValue": null,
    "editable": true,
    "requiresReboot": false,
    "encrypt": true,
    "description": "Database password, stored encrypted at rest."
  }
]

Build and Read

Section titled “Build and Read”

Pass the rows to the constructor with the accessor doing the reading. The result is built once, deep-frozen, and read by notation path:

import { Configuard, AccessorType } from 'configuard';


const cfg = new Configuard(rows, { accessor: AccessorType.SYSTEM });


cfg.data;
// {
//   company: { name: 'Acme' },
//   device: {
//     port: 8080,
//     config: { updateOnBoot: true, lifeSpan: 1440 },
//     ui: { accent: 'Amber' },
//     protocol: { transports: ['http', 'mqtt'] },
//     diagnostics: { uploadUrl: 'https://device.local/upload' }
//   },
//   environment: { host: 'device.local' },
//   db: { password: 'enc:5f3a9c2e7b104d8f' }  // encrypted — no decrypt hook here
// }


cfg.get<number>('device.port');        // 8080         — a number, not "8080"
cfg.get('device.protocol.transports'); // ['http', 'mqtt']
cfg.has('device.ui.accent');           // true

Note what the build did for you: strings were cast to their declared type ("8080" → 8080), the array row was split into a list, the ${environment.host} template was resolved, and the whole object was frozen so nothing downstream can mutate live config.

The Lifecycle

Section titled “The Lifecycle”

Configuard sits across the whole life of a setting, not just the read:

  1. Store — keep settings as rows in one config table.
  2. Build & use — new Configuard(rows) produces the nested, type-cast, ABAC-filtered object for your runtime. Read it via .data / .get() / .has().
  3. Edit in a UI — Configuard.parseFlat() returns the same flat list with templates resolved and option lists expanded, ready to render as form fields.
  4. Save back — Configuard.serializeFlat() validates the edits, serializes them to DB strings, and returns the diff to persist.

Configuard also fails loud: a corrupt row throws at construction rather than silently producing a partial object.

Next

Section titled “Next”