EVOLV/wiki/concepts/generalfunctions-api.md

title, created, updated, status, tags

title	created	updated	status	tags
generalFunctions API Reference	2026-03-01	2026-04-07	evolving	api generalFunctions reference

generalFunctions API Reference

Shared library (nodes/generalFunctions/) used across all EVOLV Node-RED nodes.

const { logger, outputUtils, MeasurementContainer, ... } = require('generalFunctions');

---

Table of Contents

1. Logger
2. OutputUtils
3. ValidationUtils
4. MeasurementContainer
5. ConfigManager
6. ChildRegistrationUtils
7. MenuUtils
8. EndpointUtils
9. Positions
10. AssetLoader / loadCurve

---

Logger

Structured, level-filtered console logger.

File: src/helper/logger.js

Constructor

new Logger(logging = true, logLevel = 'debug', nameModule = 'N/A')

Param	Type	Default	Description
logging	boolean	true	Enable/disable all output
logLevel	string	'debug'	Minimum severity: 'debug' | 'info' | 'warn' | 'error'
nameModule	string	'N/A'	Label prefixed to every message

Methods

Method	Signature	Description
debug	(message: string): void	Log at DEBUG level
info	(message: string): void	Log at INFO level
warn	(message: string): void	Log at WARN level
error	(message: string): void	Log at ERROR level
setLogLevel	(level: string): void	Change minimum level at runtime
toggleLogging	(): void	Flip logging on/off

Example

const Logger = require('generalFunctions').logger;
const log = new Logger(true, 'info', 'MyNode');
log.info('Node started');    // [INFO] -> MyNode: Node started
log.debug('ignored');        // silent (below 'info')
log.setLogLevel('debug');
log.debug('now visible');    // [DEBUG] -> MyNode: now visible

---

OutputUtils

Tracks output state and formats messages for InfluxDB or process outputs. Only emits changed fields.

File: src/helper/outputUtils.js

Constructor

new OutputUtils()   // no parameters

Methods

Method	Signature	Returns	Description
formatMsg	(output, config, format)	object | undefined	Diff against last output; returns formatted msg or undefined if nothing changed
checkForChanges	(output, format)	object	Returns only the key/value pairs that changed since last call

format must be 'influxdb' or 'process'.

Example

const out = new OutputUtils();
const msg = out.formatMsg(
  { temperature: 22.5, pressure: 1013 },
  config,
  'influxdb'
);
// msg = { topic: 'nodeName', payload: { measurement, fields, tags, timestamp } }

---

ValidationUtils

Schema-driven config validation with type coercion, range clamping, and nested object support.

File: src/helper/validationUtils.js

Constructor

new ValidationUtils(loggerEnabled = true, loggerLevel = 'warn')

Methods

Method	Signature	Returns	Description
validateSchema	(config, schema, name)	object	Walk the schema, validate every field, return a clean config. Unknown keys are stripped. Missing keys get their schema default.
constrain	(value, min, max)	number	Clamp a numeric value to [min, max]
removeUnwantedKeys	(obj)	object	Strip rules/description metadata, collapse default values

Supported rules.type values: number, integer, boolean, string, enum, array, set, object, curve, machineCurve.

Example

const ValidationUtils = require('generalFunctions').validation;
const v = new ValidationUtils(true, 'warn');

const schema = {
  temperature: { default: 20, rules: { type: 'number', min: -40, max: 100 } },
  unit:        { default: 'C', rules: { type: 'enum', values: [{ value: 'C' }, { value: 'F' }] } }
};

const validated = v.validateSchema({ temperature: 999 }, schema, 'myNode');
// validated.temperature === 100  (clamped)
// validated.unit === 'C'         (default applied)

---

MeasurementContainer

Chainable measurement storage organised by type / variant / position. Supports auto unit conversion, windowed statistics, events, and positional difference calculations.

File: src/measurements/MeasurementContainer.js

Constructor

new MeasurementContainer(options = {}, logger)

Option	Type	Default	Description
windowSize	number	10	Rolling window for statistics
defaultUnits	object	{ pressure:'mbar', flow:'m3/h', ... }	Default unit per measurement type
autoConvert	boolean	true	Auto-convert values to target unit
preferredUnits	object	{}	Per-type unit overrides

Chainable Setters

All return this for chaining.

container
  .type('pressure')
  .variant('static')
  .position('upstream')
  .distance(5)
  .unit('bar')
  .value(3.2, Date.now(), 'bar');

Method	Signature	Description
type	(typeName): this	Set measurement type (e.g. 'pressure')
variant	(variantName): this	Set variant (e.g. 'static', 'differential')
position	(positionValue): this	Set position (e.g. 'upstream', 'downstream')
distance	(distance): this	Set physical distance from parent
unit	(unitName): this	Set unit on the underlying measurement
value	(val, timestamp?, sourceUnit?): this	Store a value; auto-converts if sourceUnit differs from target

Terminal / Query Methods

Method	Signature	Returns	Description
get	()	Measurement | null	Get the raw measurement object
getCurrentValue	(requestedUnit?)	number | null	Latest value, optionally converted
getAverage	(requestedUnit?)	number | null	Windowed average
getMin	()	number | null	Window minimum
getMax	()	number | null	Window maximum
getAllValues	()	array | null	All stored samples
getLaggedValue	(lag?, requestedUnit?)	number | null	Value from lag samples ago
getLaggedSample	(lag?, requestedUnit?)	object | null	Full sample { value, timestamp, unit } from lag samples ago
exists	({ type?, variant?, position?, requireValues? })	boolean	Check if a measurement series exists
difference	({ from?, to?, unit? })	object | null	Compute { value, avgDiff, unit } between two positions

Introspection / Lifecycle

Method	Signature	Returns	Description
getTypes	()	string[]	All registered measurement types
getVariants	()	string[]	Variants under current type
getPositions	()	string[]	Positions under current type+variant
getAvailableUnits	(measurementType?)	string[]	Units available for a type
getBestUnit	(excludeUnits?)	object | null	Best human-readable unit for current value
setPreferredUnit	(type, unit)	this	Override default unit for a type
setChildId	(id)	this	Tag container with a child node ID
setChildName	(name)	this	Tag container with a child node name
setParentRef	(parent)	this	Store reference to parent node
clear	()	void	Reset all measurements and chain state

Events

The internal emitter fires "type.variant.position" on every value() call with:

{ value, originalValue, unit, sourceUnit, timestamp, position, distance, variant, type, childId, childName, parentRef }

Example

const { MeasurementContainer } = require('generalFunctions');
const mc = new MeasurementContainer({ windowSize: 5 });

mc.type('pressure').variant('static').position('upstream').value(3.2);
mc.type('pressure').variant('static').position('downstream').value(2.8);

const diff = mc.type('pressure').variant('static').difference();
// diff = { value: -0.4, avgDiff: -0.4, unit: 'mbar', from: 'downstream', to: 'upstream' }

---

ConfigManager

Loads JSON config files from disk and builds merged runtime configs.

File: src/configs/index.js

Constructor

new ConfigManager(relPath = '.')

relPath is resolved relative to the configs directory.

Methods

Method	Signature	Returns	Description
getConfig	(configName)	object	Load and parse <configName>.json
getAvailableConfigs	()	string[]	List config names (without .json)
hasConfig	(configName)	boolean	Check existence
getBaseConfig	()	object	Shortcut for getConfig('baseConfig')
buildConfig	(nodeName, uiConfig, nodeId, domainConfig?)	object	Merge base schema + UI overrides into a runtime config
createEndpoint	(nodeName)	string	Generate browser JS that injects config into window.EVOLV.nodes

Example

const { configManager } = require('generalFunctions');
const cfg = configManager.buildConfig('measurement', uiConfig, node.id, {
  scaling: { enabled: true, inputMin: 0, inputMax: 100 }
});

---

ChildRegistrationUtils

Manages parent-child node relationships: registration, lookup, and structure storage.

File: src/helper/childRegistrationUtils.js

Constructor

new ChildRegistrationUtils(mainClass)

mainClass is the parent node instance (must expose .logger and optionally .registerChild()).

Methods

Method	Signature	Returns	Description
registerChild	(child, positionVsParent, distance?)	Promise<any>	Register a child node under the parent. Sets up parent refs, measurement context, and stores by softwareType/category.
getChildrenOfType	(softwareType, category?)	array	Get children filtered by software type and optional category
getChildById	(childId)	object | null	Lookup a single child by its ID
getAllChildren	()	array	All registered children
logChildStructure	()	void	Debug-print the full child tree

Example

const { childRegistrationUtils: CRU } = require('generalFunctions');
const cru = new CRU(parentNode);
await cru.registerChild(sensorNode, 'upstream');
cru.getChildrenOfType('measurement');  // [sensorNode]

---

MenuUtils

Browser-side UI helper for Node-RED editor. Methods are mixed in from separate modules: toggles, data fetching, URL utils, dropdown population, and HTML generation.

File: src/helper/menuUtils.js

Constructor

new MenuUtils()   // no parameters; sets isCloud=false, configData=null

Key Methods

Toggles -- control UI element visibility:

Method	Signature	Description
initBasicToggles	(elements)	Bind log-level row visibility to log checkbox
initMeasurementToggles	(elements)	Bind scaling input rows to scaling checkbox
initTensionToggles	(elements, node)	Show/hide tension row based on interpolation method

Data Fetching:

Method	Signature	Returns	Description
fetchData	(url, fallbackUrl)	Promise<array>	Fetch JSON from primary URL; fall back on failure
fetchProjectData	(url)	Promise<object>	Fetch project-level data
apiCall	(node)	Promise<object>	POST to asset-register API

URL Construction:

Method	Signature	Returns	Description
getSpecificConfigUrl	(nodeName, cloudAPI)	{ cloudConfigURL, localConfigURL }	Build cloud + local config URLs
constructUrl	(base, ...paths)	string	Join URL segments safely
constructCloudURL	(base, ...paths)	string	Same as constructUrl, for cloud endpoints

Dropdown Population:

Method	Signature	Description
fetchAndPopulateDropdowns	(configUrls, elements, node)	Cascading supplier > subType > model > unit dropdowns
populateDropdown	(htmlElement, options, node, property, callback?)	Fill a <select> with options and wire change events
populateLogLevelOptions	(logLevelSelect, configData, node)	Populate log-level dropdown from config
populateSmoothingMethods	(configUrls, elements, node)	Populate smoothing method dropdown
populateInterpolationMethods	(configUrls, elements, node)	Populate interpolation method dropdown
generateHtml	(htmlElement, options, savedValue)	Write <option> HTML into an element

---

EndpointUtils

Server-side helper that serves MenuUtils as browser JavaScript via Node-RED HTTP endpoints.

File: src/helper/endpointUtils.js

Constructor

new EndpointUtils({ MenuUtilsClass? })

Param	Type	Default	Description
MenuUtilsClass	class	MenuUtils	The MenuUtils constructor to introspect

Methods

Method	Signature	Returns	Description
createMenuUtilsEndpoint	(RED, nodeName, customHelpers?)	void	Register GET /<nodeName>/resources/menuUtils.js
generateMenuUtilsCode	(nodeName, customHelpers?)	string	Produce the browser JS string (introspects MenuUtils.prototype)

Example

const EndpointUtils = require('generalFunctions/src/helper/endpointUtils');
const ep = new EndpointUtils();
ep.createMenuUtilsEndpoint(RED, 'valve');
// Browser can now load: GET /valve/resources/menuUtils.js

---

Positions

Canonical constants for parent-child spatial relationships.

File: src/constants/positions.js

Exports

const { POSITIONS, POSITION_VALUES, isValidPosition } = require('generalFunctions');

Export	Type	Value
POSITIONS	object	{ UPSTREAM: 'upstream', DOWNSTREAM: 'downstream', AT_EQUIPMENT: 'atEquipment', DELTA: 'delta' }
POSITION_VALUES	string[]	['upstream', 'downstream', 'atEquipment', 'delta']
isValidPosition	(pos: string): boolean	Returns true if pos is one of the four values

---

AssetLoader / loadCurve

Loads JSON asset files (machine curves, etc.) from the datasets directory with LRU caching.

File: datasets/assetData/curves/index.js

Singleton convenience functions

const { loadCurve } = require('generalFunctions');

Function	Signature	Returns	Description
loadCurve	(curveType: string)	object | null	Load <curveType>.json from the curves directory
loadAsset	(datasetType, assetId)	object | null	Load any JSON asset by dataset folder and ID
getAvailableAssets	(datasetType)	string[]	List asset IDs in a dataset folder

AssetLoader class

new AssetLoader(maxCacheSize = 100)

Same methods as above (loadCurve, loadAsset, getAvailableAssets), plus clearCache().

Example

const { loadCurve } = require('generalFunctions');
const curve = loadCurve('hidrostal-H05K-S03R');
// curve = { flow: [...], head: [...], ... } or null