Add external row quantity foundation

src/domain/calculations/circuit-device-row-quantity.ts

@@ -0,0 +1,43 @@
+export interface ExternalQuantityContribution {
+  effectiveQuantity: number;
+}
+
+export function calculateCircuitDeviceRowQuantity(
+  manualQuantity: number,
+  externalObjects: ExternalQuantityContribution[]
+) {
+  assertNonNegativeFinite(manualQuantity, "Manual quantity");
+  return externalObjects.reduce((quantity, object) => {
+    assertPositiveFinite(object.effectiveQuantity, "External effective quantity");
+    return quantity + object.effectiveQuantity;
+  }, manualQuantity);
+}
+
+export function assertCircuitDeviceRowQuantity(input: {
+  quantity: number;
+  manualQuantity: number;
+  externalObjects: ExternalQuantityContribution[];
+}) {
+  assertNonNegativeFinite(input.quantity, "Materialized quantity");
+  const expected = calculateCircuitDeviceRowQuantity(
+    input.manualQuantity,
+    input.externalObjects
+  );
+  if (input.quantity !== expected) {
+    throw new Error(
+      `Materialized quantity ${input.quantity} does not match manual and external quantity ${expected}.`
+    );
+  }
+}
+
+function assertNonNegativeFinite(value: number, label: string) {
+  if (!Number.isFinite(value) || value < 0) {
+    throw new Error(`${label} must be a non-negative finite number.`);
+  }
+}
+
+function assertPositiveFinite(value: number, label: string) {
+  if (!Number.isFinite(value) || value <= 0) {
+    throw new Error(`${label} must be a positive finite number.`);
+  }
+}