Polar Parcels — Lab 2 (MVP, TypeScript)

Small CLI that loads a workday (drivers, vehicles, weather, jobs), computes quotes, assigns feasible (driver, vehicle) pairs, and outputs a Daily Manifest and summary.json. Designed for change with pluggable pricing rules and a swap-able assignment strategy.

Prerequisites

• Node.js 18+ (tested on Node 22)
• npm
• (recommended) VS Code

Install, Build, Run

npm install
npm run build
node dist/app.js

CLI Commands

At the > prompt:

help import data price all assign all print manifest export summary quit

What they do

import

— loads JSON from a folder (default data) price all — prints quotes for every (job × vehicle) assign all — greedy feasible assignment using the quotes print manifest — writes out/manifest.txt and echoes it export summary — writes out/summary.json

Data Files (in /data)

drivers.json, vehicles.json, weather.json, jobs.json

Outputs (in /out)

manifest.txt — plain-text daily manifest (printable) summary.json — compact JSON for downstream systems

Architecture (quick tour)

Domain models: domain/models.ts Pricing: domain/pricing/BasePricingEngine.ts with pluggable

IPriceRule rules:

BaseFeeRule (flat $5/job) PerKmByVehicleRule (car $0.80/km, snowmobile $0.60/km, cargo-bike $0.35/km) WeatherSurchargeRule (+10% if snow or < −10°C) LakeEffectAlertRule (extension proof) (+8% if alert contains “lake-effect-snow”) PriorityRule (×1.25 for express)

Assignment: domain/assign/GreedyAssignment.ts (feasibility: capacity, range, terrain; chooses cheapest feasible vehicle; picks any licensed free driver)

I/O boundary: io/loader.ts (reads JSON, trims BOM) & io/printer.ts (writes manifest/summary)

Wiring/DI: app.ts injects rule instances into BasePricingEngine and the GreedyAssignment strategy

Computation Order

Base fee ($5) Distance cost (vehicle rate × km) Weather surcharge (+10% if snow or < −10°C) Lake-effect alert (+8% if present) Priority multiplier (×1.25 if express)

Sample Results (with provided data)

J-1001 urban, standard (12.5 km) car: $17.82, snowmobile: $14.85, cargo-bike: $11.14 J-1002 backcountry, express (85 km) car: $108.41 (car disallowed for backcountry) snowmobile: $83.16 cargo-bike: $51.59 (bike disallowed for backcountry)

Greedy assignment (default data): Assigned 1/2 jobs. (J-1002 fails range: needs 204 km round-trip with buffer; snowmobile has 120 km)

To make J-1002 assignable for a demo, bump the snowmobile rangeKm to ≥ 204 in data/vehicles.json, then import data → assign all → print manifest.

Extensibility (proof)

Add a pricing rule by creating a new class implementing IPriceRule and registering it in app.ts. Example: LakeEffectAlertRule added without editing the engine. To demonstrate, comment it out in app.ts and observe ~8% lower quotes where applicable.

Troubleshooting

tsc not found: npm i -D typescript then npx tsc ERR_MODULE_NOT_FOUND: Ensure "type": "commonjs" in package.json and rebuild “not a module” TS2306: Make sure files export something (export class…, export function…)