@elite-dangerous-almanac/core / Building an outfitting screen

Everything a shipyard screen shows, end to end: enumerate the hull's mounts, offer only what fits, fit it, and report what the build now does. All of it hangs off ShipLoadout.

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';
import type { LoadoutEvent } from '@elite-dangerous-almanac/core/ships/slef';

// A hull on its stock bulkhead, core internals and cargo hatch, nothing else fitted…
const fresh = ShipLoadout.empty('Anaconda');

// …or the build a commander is already flying.
declare const event: LoadoutEvent;
const owned = ShipLoadout.fromLoadout(event);

slots() returns every mount on the hull, occupied or not, in layout order. Pass a kind to narrow it.

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';

const build = ShipLoadout.empty('Anaconda');

build.slots().length; // -> 39
build.slots('optional').length; // -> 14
build.slots('hardpoint').length; // -> 8

const slot = build.slots('optional')[0];
slot?.key; // the identifier every mutation takes
slot?.name; // the label to render
slot?.size; // the class of module it accepts
slot?.module; // null while the mount is empty

Slot keys come from the game and are not derivable from position. Frontier writes FrameShiftDrive, Slot01_Size6, HugeHardpoint1; a SLEF producer may lower-case them. Read the key rather than composing one — matching is case-insensitive either way.

The views are snapshots. After an edit, call slots() again rather than re-reading a value you captured earlier.

modulesForSlot filters the complete module catalogue down to the modules that mount will actually accept, by size and by restriction. Size is usually an upper bound — a smaller module may be underfitted into a larger mount — but a Supercruise Overcharge frame shift drive is sold at one size only, so a drive mount offers the SCO drives of its own size and no smaller ones.

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';

const build = ShipLoadout.empty('Anaconda');

const drives = build.modulesForSlot('FrameShiftDrive');
drives.map((m) => m.symbol); // every drive that fits, largest class included

const optional = build.modulesForSlot('Slot01_Size7');
const cargoRacks = optional.filter((module) => module.familyId === 'cargoRacks');

The method searches the whole module catalogue because some mounts accept modules from more than one outfitting category: a fuel tank is a core module that also fits optional mounts. ShipLoadout already carries the complete catalogue for whole-build operations.

What it never offers is the grantOnly articles — the starter *_free fittings and the bundle-granted Vessel Hangars — because each is a second identity for a module the game already sells. Offer them and the thruster list shows "2E Thrusters" twice, the second one unpriced. A build that arrived carrying one keeps it, and getModuleBySymbol still resolves it; only the choices are filtered.

The Cargo Hatch is left out for a different reason: it is a built-in hull module. The source registry files it with the optional internals, which is where INTERNAL_MODULES carries it, but the hull is built with one and the fixed CargoHatch mount is the only place it goes — so no mount your screen can edit offers or accepts it. Fitting one anywhere else is refused with the builtInHullModule constraint.

Every module carries a familyId, core modules included, so the whole result of modulesForSlot groups without a taxonomy of your own. Related variants share one family: Bi-Weave and Prismatic generators are all shieldGenerators, and a pre-engineered or Powerplay weapon stays with its base weapon.

OUTFITTING_FAMILIES gives the canonical English heading for a family, and getOutfittingFamilyName gives a localized one — null where the sources carry no label for that locale, so your application chooses the fallback rather than being handed English dressed up as a translation.

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';
import {
    OUTFITTING_FAMILIES,
    type OutfittingFamilyId,
} from '@elite-dangerous-almanac/core/ships/module-families';
import { getOutfittingFamilyName } from '@elite-dangerous-almanac/core/i18n/module-families';

const build = ShipLoadout.empty('Anaconda');

const byFamily = new Map<OutfittingFamilyId, string[]>();
for (const module of build.modulesForSlot('Slot01_Size7')) {
    byFamily.set(module.familyId, [...(byFamily.get(module.familyId) ?? []), module.symbol]);
}

const heading = (familyId: OutfittingFamilyId, locale: string) =>
    getOutfittingFamilyName(familyId, locale) ?? OUTFITTING_FAMILIES[familyId];

heading('shieldGenerators', 'de'); // -> 'Schildgeneratoren'
heading('xenoScanners', 'de'); // -> 'Xeno Scanners', the English fallback this app chose

A family is the heading, not the whole label: one family can hold two product lines the game sells side by side. The fsd family holds both drive lines, and which one a record belongs to is a field on it rather than something to recover from its symbol:

import { CORE_MODULES } from '@elite-dangerous-almanac/core/ships/modules-core';

const drives = CORE_MODULES.filter((module) => module.slot === 'frameShiftDrive');
drives.some((module) => module.supercruiseOvercharge); // -> true, the SCO line
drives.some((module) => !module.supercruiseOvercharge); // -> true, the ordinary line

Mutations return this, so they chain. The build is mutable — this is the one place in the library that is.

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';
import { getModuleBySymbol } from '@elite-dangerous-almanac/core/ships/modules';
import { CORE_MODULES } from '@elite-dangerous-almanac/core/ships/modules-core';

const build = ShipLoadout.empty('Anaconda');
const fsd = getModuleBySymbol('Int_Hyperdrive_Size6_Class5', CORE_MODULES)!;

build.setModule('FrameShiftDrive', fsd).applyBlueprint('FrameShiftDrive', 'FSD_LongRange', {
    grade: 5,
    experimentalEffectSymbol: 'special_fsd_heavy',
});

build.removeModule('Slot01_Size7');
build.setModuleEnabled('FrameShiftDrive', true);
build.setModulePriority('FrameShiftDrive', 1);

availableBlueprints(slotKey) returns candidate engineering routes for the fitted module symbol. A candidate's route is 'ordinary' when the stock module can take it or 'mercenary' when it requires the matching Mercenary purchase. Stock and Mercenary articles share a module symbol, so show that route in the UI and confirm the purchase before treating a Mercenary candidate as applicable. availableExperimentalEffects answers the stock module's ordinary experimental menu.

Each metric is one call on a BuildMetrics attached to the build with BuildMetrics.of(build). The figures below are one build's — a Federal Corvette.

import type { BuildMetrics } from '@elite-dangerous-almanac/core/ships/build-metrics';

declare const metrics: BuildMetrics; // BuildMetrics.of(build), a Federal Corvette

metrics.powerBudget().available; // -> 50.4     MW the plant makes
metrics.powerBudget().deployed; // -> 46.8597  MW drawn, hardpoints out
metrics.powerBudget().withinBudget; // -> true
metrics.powerBudget().bands.length; // -> 5        the five priority groups

metrics.shieldMetricsResult().value?.strength; // -> 3940.4   MJ
metrics.shieldMetricsResult().value?.resistances.kinetic; // the generator and boosters, no pips
metrics.shieldCapacitorMetricsResult().value?.effectiveResistances.kinetic; // with four pips to SYS
metrics.armourMetrics().hitPoints; // -> 5062.6

metrics.weaponMetrics().total.damagePerSecond; // -> 137.04
metrics.weaponMetrics().total.sustainedDamagePerSecond; // -> 133.98
metrics.weaponMetrics().weapons.length; // -> 7

Jump range comes in the loads that matter, so a screen does not have to compute them:

import type { BuildMetrics } from '@elite-dangerous-almanac/core/ships/build-metrics';

declare const metrics: BuildMetrics;

const jumps = metrics.jumpRangeSummary();
jumps.max; // best single jump: one jump's fuel, empty hold
jumps.unladen; // full tank, empty hold
jumps.laden; // full tank, full hold
jumps.totalMax.range; // the same best jump as a one-jump total
jumps.totalMax.jumps; // one jump when the build carries fuel
jumps.totalUnladen.range; // every jump on one tank, empty
jumps.totalUnladen.jumps; // number of jumps on that tank
jumps.totalLaden.range; // every jump on one tank, full

Mass and mobility come as figures rather than as ingredients, so the panel's mass line and its speed line are both one call:

import type { BuildMetrics } from '@elite-dangerous-almanac/core/ships/build-metrics';

declare const metrics: BuildMetrics;

const mass = metrics.buildMass();
mass.hull; // the bare hull, in tonnes
mass.modules; // every fitted module, post-engineering
mass.total; // with a full main tank and an empty hold

const mobility = metrics.mobilityMetricsResult().value;
mobility?.speed; // m/s, at four ENG pips
mobility?.loadedMass; // the mass that speed was calculated at
metrics.mobilityCapacitorMetricsResult({ enginesPips: 2 }).value?.speed; // m/s, at two
metrics.thrusters()?.optMass; // rated performance at or below this mass
metrics.thrusters()?.maxMass; // past this the ship does not move at all

The three capacity lines sit on the build itself rather than on BuildMetrics, because each is a property of what is fitted, not a calculation over it:

import { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';

const liner = ShipLoadout.default('Orca');

liner.cargoCapacity; // -> 24   tonnes, summed over the fitted racks
liner.passengerCapacity; // -> 40   berths, summed over the fitted cabins
liner.fuelCapacity.main; // -> 32   tonnes the drive can burn

cargoCapacity and fuelCapacity prefer a capture's own figure where it has one; passengerCapacity is always the sum, because no capture states a passenger figure.

A passenger panel usually wants the split by class as well as the total, and no stat field carries the class: group on the _Class1–_Class4 suffix of each cabin's symbol, which is economy, business, first and luxury on both cabin lines (the Mk II line stops at business). Do not group on rating — the Mk II cabins run one rating better than the Mk I cabins of the same class, so D is economy on one line and business on the other.

The game's statistics panel counts the reserve tank in the current mass it displays; nothing here does, so add fuelCapacity.reserve if you are reproducing that reading. Build metrics covers the mass curve those three thruster figures describe.

powerBudget().bands is what drives a priority-group table: a group is powered when its running total — its own draw plus every higher-priority group's — fits in available.

Two different questions, deliberately kept apart:

import type { ShipLoadout } from '@elite-dangerous-almanac/core/ships/ship-loadout';

declare const build: ShipLoadout;

const validation = build.validation();
validation.valid; // is the fit structurally legal?
validation.complete; // legal *and* every operational mount filled
validation.issues; // what specifically, with a stable code per issue

Branch on each issue's code, not on its severity — the codes are the stable contract, and one severity covers problems that belong in different places on the panel. The failure model explains the codes and covers the …Result methods for mobility, shields and shield recovery. On an imported build, read build.importOutcomes alongside the issues: validation says nothing about normalization, so an empty mount on your panel may be one the player left empty or one import emptied for them.

Two things follow for the panel itself. An issue's slot is not a promise that the mount exists, so drive the placement off your own layout rather than off the code: look the key up among the slots you are rendering, mark it there if it resolves, and fall through to an off-panel list if it does not. That list is not an edge case — unknownSlot carries a key that is by definition no mount on this hull. And on a build complete tracks valid: every build fills its core and armour mounts, so the missingRequiredSlot half of the question only reaches you from validateLoadout on a list of your own.

One issue on this panel is not about where a module went: thrusterMassExceeded says the thrusters the player just picked are rated below what the ship now weighs, and above that rating the mass curve gives nothing back, so the ship does not move at all. It is the one code that carries figures — params.mass and params.maxMass, in tonnes — so mark the thruster mount with them rather than with the generic message. Reach for it when a swap elsewhere on the panel adds mass too: a heavier module in an optional mount can invalidate a thruster choice the player made ten edits ago, and re-reading validation() after every edit is what surfaces that.

It also carries params.load, naming which of the ship's three loads the rating failed at — dry, unladen (a full main tank) or laden (a full hold as well). The first two are errors, and the third is the panel's one warning severity: a hauler that only outgrows its thrusters with the hold full is still a legal build, so it stays valid and complete and reaches you through issues alone. Put that one beside the cargo figure rather than on the thruster mount — the fix is usually to carry less, not to refit.

• Working with SLEF
• The failure model
• Complete API reference