core/ Pure logic

Seven modules of pure domain logic. None import React, call fetch(), or touch localStorage. Every function takes inputs and returns outputs. This makes them trivially testable in Node without a DOM.

Parent

src/

Consumed by

PlannerContext.jsx (exclusively)

Rule

No React, no I/O, no side effects — pure functions only

Children

module (~500 lines)

gradRequirements.js

Validates placed courses against a Major2 requirement tree. The most algorithmically complex module.

module (~80 lines)

prereqEval.js

Evaluates whether a course's prerequisites are met. Returns satisfied / order-violation / missing.

module (~120 lines)

courseModel.js

Normalizes raw catalog JSON into internal course objects. Extracts prereq/coreq edges. Hashes subject colors.

module (~80 lines)

semGrid.js

Generates semester grids from cohort dates. Computes SEM_INDEX, SEM_NEXT, SEM_PREV lookup maps.

module (~200 lines)

planModel.js

Plan display helpers: SH totals, ordered course lists, edge lookups. Also: async PDF export via browser print.

constants + theme tokens

constants.js + themes.js

Global compile-time constants (colors, labels, templates) and CSS variable token sets for each theme.

Inter-module dependencies

constants.js is the only internal dependency. All other modules are independent of each other.

How PlannerContext uses core

PlannerContext is the only file that imports from core/. It calls these functions during:

Event	Core function called
Courses loaded	`normalizeCourse()` for each, `buildCourseMap()`
Entry/grad dates change	`buildCohortSemesters()`, `deriveSemMaps()`
Any placement change	`evalPrereqTree()` for all placed courses → violations
User selects major	`allocateMajorWithElectives()`, `getNuPathCoverage()`
Course selected	`getConnections()` → SVG line positions
PDF export triggered	`exportReport()`