Willem van den Ende
d3cc48c0f7
- Level value object (1..10, level-capped health) - Health value object (non-negative, pure sub/add) - Status discriminated union (alive | dead) - Character entity with private constructor and static factory - 9 fast-check properties covering creation invariants - Allium spec with entities, rules, and invariants
42 lines
996 B
TypeScript
42 lines
996 B
TypeScript
/**
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* Level value object — constrained to 1..10.
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*
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* "I can't believe it's not Haskell": invalid states are unrepresentable.
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*/
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export class Level {
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#value: number;
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private constructor(n: number) {
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this.#value = n;
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}
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static create(n: number): Level {
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if (n < 1 || n > 10) {
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throw new Error(`Level must be between 1 and 10, got ${n}`);
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}
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return new Level(n);
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}
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get value(): number {
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return this.#value;
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}
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/** Difference in levels (target - this). Positive means target is higher. */
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diff(other: Level): number {
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return other.value - this.value;
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}
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/** Next level, or throws if already at max. */
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next(): Level {
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if (this.#value >= 10) {
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throw new Error('Cannot level up beyond level 10');
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}
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return Level.create(this.#value + 1);
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}
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/** Maximum health for this level: 1000 until level 6, 1500 from level 6 onward. */
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static maxHealthForLevel(level: number): number {
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return level >= 6 ? 1500 : 1000;
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}
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}
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