62 lines
2.5 KiB
TypeScript
62 lines
2.5 KiB
TypeScript
import { describe, expect, it } from 'vitest';
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import { mapNumberRange } from './map-number-range';
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describe('mapNumberRange', () => {
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it('should map a value from the source range to the target range (normal range)', () => {
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expect(mapNumberRange(5, 0, 10, 0, 100)).toBe(50);
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expect(mapNumberRange(0, 0, 10, 0, 100)).toBe(0);
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expect(mapNumberRange(10, 0, 10, 0, 100)).toBe(100);
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});
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it('should map values outside the source range', () => {
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expect(mapNumberRange(-5, 0, 10, 0, 100)).toBe(-50); // Extrapolate below source range
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expect(mapNumberRange(15, 0, 10, 0, 100)).toBe(150); // Extrapolate above source range
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});
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it('should handle inverted source ranges', () => {
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// Source range is 10 to 0, mapping 5 should be halfway
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// Target range is 100 to 0, so halfway is 50
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expect(mapNumberRange(5, 10, 0, 100, 0)).toBe(50);
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// Outside inverted range
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expect(mapNumberRange(15, 10, 0, 100, 0)).toBe(150);
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expect(mapNumberRange(-5, 10, 0, 100, 0)).toBe(-50);
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});
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it('should handle inverted target ranges', () => {
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// Normal source range, but inverted target
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expect(mapNumberRange(5, 0, 10, 100, 0)).toBe(50);
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expect(mapNumberRange(0, 0, 10, 100, 0)).toBe(100);
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expect(mapNumberRange(10, 0, 10, 100, 0)).toBe(0);
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});
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it('should handle zero-length source range', () => {
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// If the source range is a single point
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expect(mapNumberRange(5, 10, 10, 0, 100)).toBe(0); // Returns start of target range
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expect(mapNumberRange(10, 10, 10, 20, 40)).toBe(20); // Returns start of target range
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});
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it('should handle negative numbers and other ranges', () => {
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expect(mapNumberRange(-10, -20, 0, 0, 100)).toBe(50);
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// Here: num = -10, source = [-20,0], target = [0,100]
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// Mapping: (-10 - (-20)) / (0 - (-20)) = 10/20 = 0.5 -> 0 + 0.5*100 = 50
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});
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it('should handle floating point values', () => {
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expect(mapNumberRange(2.5, 0, 10, 0, 100)).toBe(25); // Fractional input
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expect(mapNumberRange(1.5, 0, 3, 0, 1)).toBeCloseTo(0.5, 6); // Precision check
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});
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it('should handle large ranges', () => {
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expect(mapNumberRange(500, 0, 1000, 0, 1_000_000)).toBe(500_000);
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});
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it('should handle screen coordinates to world correctly', () => {
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expect(mapNumberRange(100, 0, 1000, 1000, 0)).toBe(900);
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});
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it('should handle world coordinates to screen correctly', () => {
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expect(mapNumberRange(900, 1000, 0, 0, 1000)).toBe(100);
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});
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});
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