@metrics/metric/lib/is.js

The metric class definition which metric objects in the @metrics library is instansiated from

"use strict";

// Ref; https://github.com/OpenObservability/OpenMetrics/blob/9a6db2a94dcf8dd84dd08a221e1b323e2b279f08/proto/openmetrics_data_model.proto#L42
const REGEX_NAME = /^[a-zA-Z_:][a-zA-Z0-9_:]*$/;

const isString = (value) => {
	return typeof value === "string";
};
module.exports.isString = isString;

const isEmptyString = (value) => {
	return value.trim().length === 0;
};
module.exports.isEmptyString = isEmptyString;

const notEmpty = (value) => {
	if (value === undefined) {
		return false;
	}

	if (value === null) {
		return false;
	}

	if (isString(value) && isEmptyString(value)) {
		return false;
	}

	return true;
};
module.exports.notEmpty = notEmpty;

const validName = (value) => {
	return REGEX_NAME.test(value);
};
module.exports.validName = validName;

const validType = (value) => {
	return value >= 0 && value <= 7;
};
module.exports.validType = validType;

const validDescription = (value) => {
	return isString(value) || value === null || value === undefined;
};
module.exports.validDescription = validDescription;

const validSource = (value) => {
	return isString(value) || value === null || value === undefined;
};
module.exports.validSource = validSource;

const validTimestamp = (value) => {
	return Number.isFinite(value) || value === null || value === undefined;
};
module.exports.validTimestamp = validTimestamp;

const validValue = (value) => {
	return Number.isFinite(value) || value === null || value === undefined;
};
module.exports.validValue = validValue;

const validLabelValue = (value) => {
	return (
		typeof value === "boolean" || Number.isFinite(value) || isString(value) || value === null || value === undefined
	);
};
module.exports.validLabelValue = validLabelValue;

const validLabel = (value) => {
	if (typeof value !== "object") {
		return false;
	}

	if (!("name" in value) || !("value" in value)) {
		return false;
	}

	if (!REGEX_NAME.test(value.name)) {
		return false;
	}

	return validLabelValue(value.value);
};
module.exports.validLabel = validLabel;

const validLabels = (value) => {
	if (!Array.isArray(value)) {
		return false;
	}

	if (value.length === 0) {
		return true;
	}

	const valid = value.filter(validLabel);

	return value.length === valid.length;
};
module.exports.validLabels = validLabels;