nordicsemiconductor / lwm2m-types-js

TypeScript type definitions and JSON schema for the objects defined in the LwM2M Object Registry.

LwM2M TypeScript type definitions and JSON schema

TypeScript type definitions and JSON schema for the objects defined in the LwM2M Object Registry.

This is useful if you need to validate a JSON representation of those objects.

Installation

npm ci
// Clone LwM2M object registry
git clone https://github.com/OpenMobileAlliance/lwm2m-registry.git --depth 1
npm test

Usage

See example.ts

JSON document structure

LwM2M values are encoded as a JSON document, where the key is an extended version of the LwM2M URN: <ObjectID>:<ObjectVersion>@<LwM2MVersion> (where ObjectVersion and/or LwM2MVersion can be omitted if it is 1.0).

Example

Building the types

git clone https://github.com/OpenMobileAlliance/lwm2m-registry.git --depth 1
npx tsx cli/generate-types.ts
npx tsx cli/generate-json-schema.ts
# Format the source
npx prettier --write ./
# Make sure result compiles
npx tsc
# Compile JS exports
npx swc -d types-dist ./types
# Make sure example runs
npx tsx ./example.ts

lwm2m-types-js's Issues

Update from LwM2M registry fails

https://github.com/NordicSemiconductor/lwm2m-types-js/actions/runs/6871311470

Use fluent-json-schema to generate schema from LwM2M object definition

https://github.com/fastify/fluent-json-schema

This library already has the fluent API we use for configuring TypeBox objects and we can therefore skip the factory classes.

Remove unneccessary path from tsconfig

lwm2m-types-js/tsconfig.json

Line 21 in 6fc489b

"paths": {

Use regular imports in the source code without relying on rewriting of imports through the tsconfig.

[JSON Schema] Express Time resource as custom type 'time'

Time Unix Time. A signed integer
representing the number of seconds since
Jan 1st, 1970 in the UTC time zone.
Represented as an ASCII
integer.

For example, 1476186613
seconds since Jan 01 1970,
which represents Tuesday,
11-Oct-16 11:50:13 UTC,
are represented as the
ASCII string
"1476186613", which has
10 characters/bytes.

Same representation as Integer.

Page 96 http://www.openmobilealliance.org/release/lightweightm2m/V1_0-20170208-A/OMA-TS-LightweightM2M-V1_0-20170208-A.pdf

Example

add type: time, user-defined keywords are supported in AJV: https://ajv.js.org/keywords.html

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "$id": "https://github.com/NordicSemiconductor/lwm2m-types-js/blob/saga/LwM2MDocument.schema.json",
  "title": "LwM2M JSON Schema",
  "description": "JSON schema for expressing LwM2M resources as JSON",
  "properties": {
    "6": {
      "properties": {
        "5": {
          "type": "time",
          "minimum": 1000000000,
          "title": "Timestamp",
          "description": "The timestamp of when the location measurement was performed. Unix Time. A signed integer representing the number of seconds since Jan 1 st, 1970 in the UTC time zone."
        },
      },
    },
  },
}

Update readme with steps to installation

Right now, installation steps are

npm ci
npm test

However after follow those steps, the result is

Because it is needed to clone LwM2M object registry first before run the tests

git clone https://github.com/OpenMobileAlliance/lwm2m-registry.git  --depth 1

Questions Record

Record of questions already asked and their responses:

Bug: resources defined as multiple instances are not defined as array type

Resource with id 7 from Device object (3) has the following specifications:

/**
 * Power Source Voltage
 *
 * Present voltage for each Available Power Sources Resource Instance. The unit
 * used for this resource is in mV.
 *
 * ID: 7
 * MultipleInstances: true
 * Mandatory: false
 */

The Document Schema generated by the library defines it as an array:

"7": {
          "type": "array",
          "minItems": 1,
          "items": { "type": "integer" },
          "title": "Power Source Voltage",
          "description": "Present voltage for each Available Power Sources Resource Instance. The unit used for this resource is in mV."
        },

But in order with its type definition, it is a number:

type PowerSourceVoltage_7 = number

When the expected would be an array of numbers

type PowerSourceVoltage_7 = number[]

because it is a multiple instance.

The schema defines it as an array, so it is not a problem when checking the veracity of it.

const input = {
     [Device_3_urn]: {
		'0': 'Nordic Semiconductor ASA',
		'1': 'Thingy:91',
		'2': '351358815340515',
		'3': '22.8.1+0',
		'7': [80],
		'11': [0],
		'13': 1675874731,
		'16': 'UQ',
		'19': '3.2.1',
	}
}

const maybeValidLwM2M = validate(input)
if ('errors' in maybeValidLwM2M)
     return { error: new Error(JSON.stringify(maybeValidLwM2M.errors)) }
return { result: true } // this returns here

But it is an issue when using the type definition

const device: Device_3 = {
	'0': 'Nordic Semiconductor ASA',
	'1': 'Thingy:91',
	'2': '351358815340515',
	'3': '22.8.1+0',
	'7': [2754], // Type 'number[]' is not assignable to type 'number'.
	'11': [0], // Type 'number[]' is not assignable to type 'number'
	'13': 1675874731,
	'16': 'UQ',
	'19': '3.2.1',
}

Dependency Dashboard

This issue lists Renovate updates and detected dependencies. Read the Dependency Dashboard docs to learn more.

Repository problems

These problems occurred while renovating this repository. View logs.

• WARN: Fallback to renovate.json file as a preset is deprecated, please use a default.json file instead.

Open

These updates have all been created already. Click a checkbox below to force a retry/rebase of any.

• chore(deps): update dependency typescript to v5.3.2

Ignored or Blocked

These are blocked by an existing closed PR and will not be recreated unless you click a checkbox below.

• chore(deps): update actions/setup-node action to v4

Detected dependencies

github-actions

.github/workflows/code-style.yaml

• actions/checkout v4
• actions/setup-node v3
• actions/cache v3
• peter-evans/create-pull-request v5
• ubuntu 22.04

.github/workflows/sync-issue-labels.yaml

• actions/checkout v4
• ubuntu 22.04

.github/workflows/test-and-release.yaml

• actions/checkout v4
• actions/setup-node v3
• actions/cache v3

.github/workflows/update-definitions.yaml

• actions/checkout v4
• actions/setup-node v3
• actions/cache v3
• peter-evans/create-pull-request v5
• ubuntu 22.04

.github/workflows/update-repo-info.yaml

• actions/checkout v4
• ubuntu 22.04

npm

package.json

• ajv 8.12.0
• @commitlint/config-conventional 18.4.3
• @nordicsemiconductor/asset-tracker-cloud-code-style 12.0.113
• @nordicsemiconductor/eslint-config-asset-tracker-cloud-typescript 16.0.23
• @sinclair/typebox 0.31.28
• @swc/cli 0.1.63
• @swc/core 1.3.99
• @swc/jest 0.2.29
• @types/jest 29.5.10
• @types/xml2js 0.4.14
• @typescript-eslint/eslint-plugin 6.12.0
• chalk 5.3.0
• eslint-config-prettier 9.0.0
• eslint-plugin-import 2.29.0
• eslint-plugin-prefer-arrow 1.2.3
• eslint-plugin-unicorn 49.0.0
• fluent-json-schema 4.2.1
• husky 8.0.3
• jest 29.7.0
• prettier 3.1.0
• tsmatchers 5.0.2
• tsx 4.5.0
• typescript 5.2.2
• xml2js 0.6.2
• node >=20
• npm >=9

---

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Current range of Date type do not support valid dates

Current range is

• Minimum: 1111111111
• Maximum: 9999999999

However,

• 1970-01-01T00:00:00Z is 0 in Unix Time format
• 1960-01-01T00:00:00Z is -315619200000 in Unix Time format

Unix time has it own limitations and range should address to those.