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Reference: Composition Primitives

The three functions Build a Player and Quickstart use to turn a plain class into something that behaves like NMVideoPlayer or NMMusicPlayer.

composeMixins

TypeScript
function composeMixins<T extends object>(prototype: T, ...modules: object[]): void;

Stamps one or more mixin objects onto a prototype via Object.getOwnPropertyDescriptors + Object.defineProperty, so getters/setters land as accessors instead of being triggered during the copy. Collision order is left-to-right: a later module in the argument list overrides an earlier one on the same key, list more specific modules after more general ones. Idempotent, calling it twice with the same module just overwrites identical descriptors.

resolvePlayerConstructor

TypeScript
function resolvePlayerConstructor<C>(
	id: string | number | undefined,
	instances: Map<string, C>,
	className: string,
): PlayerCtorResolution<C>;

type PlayerCtorResolution<C> =
	| { kind: 'existing'; instance: C }
	| { kind: 'mount'; id: string; div: HTMLDivElement };

The three-form factory resolution nmplayer() / nmplayer('div-id') / nmplayer(2) use. id === undefined returns the first registered instance (throws core:player/no-element if the registry is empty). A numeric id indexes the registry’s insertion order (throws core:player/not-found out of range). A string id checks the registry first; if not found, resolves document.getElementById(id) and requires it to be a <div> (throws core:player/element-missing or core:player/element-not-div). SSR-safe, the document call is guarded.

initPlayerCoreState

TypeScript
function initPlayerCoreState(player: object, opts: { className: string }): void;

Seeds every internal slot (phase 'idle', dispatch stack, cue parser registry, play/volume/repeat/shuffle state, volume 100, playback rate 1, and the rest) to its canonical starting value. Call this once in your constructor, before the instance is usable.

KIT_VERSION

TypeScript
declare const KIT_VERSION: string; // derived from package.json at compile time

Compared against a plugin’s static readonly minCoreVersion at addPlugin() time, mismatches throw core:plugin/incompatible-core-version.

playerCoreMethods and the individually-exported mixin groups

playerCoreMethods is the full as const tuple of every shared mixin, the exact aggregate NMVideoPlayer and NMMusicPlayer compose. It bundles 26 mixin groups internally, but only 16 are individually importable from the package’s public entry, the other 10 (stream registration, media tracks, device detection, audio output, cast state, ABR, metrics, loading, activity, and generic DOM helpers) are internal building blocks meant to be consumed only as part of the full aggregate, not recomposed piecemeal.

Individually exported, for composing a narrower surface than the full aggregate:

lifecycleMethods · transportMethods · timeMethods · volumeMethods · queueMethods · playQueueMethods · stateMethods · playerStateMethods · pluginRegistrationMethods · authMethods · i18nMethods · cueParserMethods · baseUrlAudioContextMethods · containerClassEmitMethods · preloadStrategyMethods · experimentalDescriptor

TypeScript
import { composeMixins, lifecycleMethods, transportMethods } from '@nomercy-entertainment/nomercy-player-core';

// A narrower composition than playerCoreMethods — only lifecycle + transport,
// for a consumer building something that genuinely doesn't need the queue,
// i18n, or plugin surface at all.
composeMixins(MyPlayer.prototype, lifecycleMethods, transportMethods);

Most consumers want the full playerCoreMethods aggregate, as every page in Build a Player does, composing a subset is an advanced move for a genuinely minimal use case.

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