Add prism

config.json

@@ -2596,6 +2596,21 @@
           "logic"
         ]
       },
+      {
+        "slug": "prism",
+        "name": "Prism",
+        "uuid": "ef463b82-bf5c-4761-a821-29eeabee3050",
+        "practices": [],
+        "prerequisites": [
+          "arithmetic-operators",
+          "arrays",
+          "array-loops",
+          "comparison",
+          "conditionals",
+          "for-loops"
+        ],
+        "difficulty": 5
+      },
       {
         "slug": "satellite",
         "name": "Satellite",

exercises/practice/prism/.docs/instructions.md

@@ -0,0 +1,36 @@
+# Instructions
+
+Before activating the laser array, you must predict the exact order in which crystals will be hit, identified by their sample IDs.
+
+## Example Test Case
+
+Consider this crystal array configuration:
+
+```json
+{
+  "start": { "x": 0, "y": 0, "angle": 0 },
+  "prisms": [
+    { "id": 3, "x": 30, "y": 10, "angle": 45 },
+    { "id": 1, "x": 10, "y": 10, "angle": -90 },
+    { "id": 2, "x": 10, "y": 0, "angle": 90 },
+    { "id": 4, "x": 20, "y": 0, "angle": 0 }
+  ]
+}
+```
+
+## What's Happening
+
+The laser starts at the origin `(0, 0)` and fires horizontally to the right at angle 0°.
+Here's the step-by-step beam path:
+
+**Step 1**: The beam travels along the x-axis (y = 0) and first encounters **Crystal #2** at position `(10, 0)`.
+This crystal has a refraction angle of 90°, which means it bends the beam perpendicular to its current path.
+The beam, originally traveling at 0°, is now redirected to 90° (straight up).
+
+**Step 2**: The beam now travels vertically upward from position `(10, 0)` and strikes **Crystal #1** at position `(10, 10)`.
+This crystal has a refraction angle of -90°, bending the beam by -90° relative to its current direction.
+The beam was traveling at 90°, so after refraction it's now at 0° (90° + (-90°) = 0°), traveling horizontally to the right again.
+
+**Step 3**: From position `(10, 10)`, the beam travels horizontally and encounters **Crystal #3** at position `(30, 10)`.
+This crystal refracts the beam by 45°, changing its direction to 45°.
+The beam continues into empty space beyond the array.

exercises/practice/prism/.docs/introduction.md

@@ -0,0 +1,5 @@
+# Introduction
+
+You're a researcher at **PRISM** (Precariously Redirected Illumination Safety Management), working with a precision laser calibration system that tests experimental crystal prisms.
+These crystals are being developed for next-generation optical computers, and each one has unique refractive properties based on its molecular structure.
+The lab's laser system can damage crystals if they receive unexpected illumination, so precise path prediction is critical.

exercises/practice/prism/.gitignore

@@ -0,0 +1,5 @@
+/node_modules
+/bin/configlet
+/bin/configlet.exe
+/package-lock.json
+/yarn.lock

exercises/practice/prism/.meta/config.json

@@ -0,0 +1,25 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "prism.js"
+    ],
+    "test": [
+      "prism.spec.js"
+    ],
+    "example": [
+      ".meta/proof.ci.js"
+    ]
+  },
+  "blurb": "Calculate the path of a laser through reflective prisms.",
+  "source": "FraSanga",
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2625",
+  "custom": {
+    "version.tests.compatibility": "jest-27",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false
+  }
+}

exercises/practice/prism/.meta/proof.ci.js

@@ -0,0 +1,41 @@
+export const findSequence = (start, prisms) => {
+  let { x, y, angle } = start;
+  const sequence = [];
+
+  while (true) {
+    const rad = (angle * Math.PI) / 180;
+    const dirX = Math.cos(rad);
+    const dirY = Math.sin(rad);
+
+    let nearest = null;
+    let nearestDist = Infinity;
+
+    for (const prism of prisms) {
+      const dx = prism.x - x;
+      const dy = prism.y - y;
+
+      const dist = dx * dirX + dy * dirY;
+      const baseTolerance = 1e-6;
+      if (dist <= baseTolerance) continue;
+
+      const crossProductSquared =
+        (dx - dist * dirX) ** 2 + (dy - dist * dirY) ** 2;
+      const relativeTolerance = baseTolerance * Math.max(1, dist * dist);
+      if (crossProductSquared >= relativeTolerance) continue;
+
+      if (dist < nearestDist) {
+        nearestDist = dist;
+        nearest = prism;
+      }
+    }
+
+    if (!nearest) break;
+
+    sequence.push(nearest.id);
+    x = nearest.x;
+    y = nearest.y;
+    angle = (angle + nearest.angle) % 360;
+  }
+
+  return sequence;
+};

exercises/practice/prism/.meta/tests.toml

@@ -0,0 +1,52 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[ec65d3b3-f7bf-4015-8156-0609c141c4c4]
+description = "zero prisms"
+
+[ec0ca17c-0c5f-44fb-89ba-b76395bdaf1c]
+description = "one prism one hit"
+
+[0db955f2-0a27-4c82-ba67-197bd6202069]
+description = "one prism zero hits"
+
+[8d92485b-ebc0-4ee9-9b88-cdddb16b52da]
+description = "going up zero hits"
+
+[78295b3c-7438-492d-8010-9c63f5c223d7]
+description = "going down zero hits"
+
+[acc723ea-597b-4a50-8d1b-b980fe867d4c]
+description = "going left zero hits"
+
+[3f19b9df-9eaa-4f18-a2db-76132f466d17]
+description = "negative angle"
+
+[96dacffb-d821-4cdf-aed8-f152ce063195]
+description = "large angle"
+
+[513a7caa-957f-4c5d-9820-076842de113c]
+description = "upward refraction two hits"
+
+[d452b7c7-9761-4ea9-81a9-2de1d73eb9ef]
+description = "downward refraction two hits"
+
+[be1a2167-bf4c-4834-acc9-e4d68e1a0203]
+description = "same prism twice"
+
+[df5a60dd-7c7d-4937-ac4f-c832dae79e2e]
+description = "simple path"
+
+[8d9a3cc8-e846-4a3b-a137-4bfc4aa70bd1]
+description = "multiple prisms floating point precision"
+
+[e077fc91-4e4a-46b3-a0f5-0ba00321da56]
+description = "complex path with multiple prisms floating point precision"

exercises/practice/prism/.npmrc

@@ -0,0 +1 @@
+audit=false

exercises/practice/prism/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

exercises/practice/prism/babel.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  presets: [['@exercism/babel-preset-javascript', { corejs: '3.40' }]],
+  plugins: [],
+};

exercises/practice/prism/eslint.config.mjs

@@ -0,0 +1,45 @@
+// @ts-check
+
+import config from '@exercism/eslint-config-javascript';
+import maintainersConfig from '@exercism/eslint-config-javascript/maintainers.mjs';
+
+import globals from 'globals';
+
+export default [
+  ...config,
+  ...maintainersConfig,
+  {
+    files: maintainersConfig[1].files,
+    rules: {
+      'jest/expect-expect': ['warn', { assertFunctionNames: ['expect*'] }],
+    },
+  },
+  {
+    files: ['scripts/**/*.mjs'],
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+    },
+  },
+  // <<inject-rules-here>>
+  {
+    ignores: [
+      // # Protected or generated
+      '/.appends/**/*',
+      '/.github/**/*',
+      '/.vscode/**/*',
+
+      // # Binaries
+      '/bin/*',
+
+      // # Configuration
+      '/config',
+      '/babel.config.js',
+
+      // # Typings
+      '/exercises/**/global.d.ts',
+      '/exercises/**/env.d.ts',
+    ],
+  },
+];

exercises/practice/prism/jest.config.js

@@ -0,0 +1,22 @@
+module.exports = {
+  verbose: true,
+  projects: ['<rootDir>'],
+  testMatch: [
+    '**/__tests__/**/*.[jt]s?(x)',
+    '**/test/**/*.[jt]s?(x)',
+    '**/?(*.)+(spec|test).[jt]s?(x)',
+  ],
+  testPathIgnorePatterns: [
+    '/(?:production_)?node_modules/',
+    '.d.ts$',
+    '<rootDir>/test/fixtures',
+    '<rootDir>/test/helpers',
+    '__mocks__',
+  ],
+  transform: {
+    '^.+\\.[jt]sx?$': 'babel-jest',
+  },
+  moduleNameMapper: {
+    '^(\\.\\/.+)\\.js$': '$1',
+  },
+};

exercises/practice/prism/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "@exercism/javascript-prism",
+  "description": "Exercism exercises in Javascript.",
+  "author": "Katrina Owen",
+  "private": true,
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/javascript",
+    "directory": "exercises/practice/prism"
+  },
+  "devDependencies": {
+    "@exercism/babel-preset-javascript": "^0.5.1",
+    "@exercism/eslint-config-javascript": "^0.8.1",
+    "@jest/globals": "^29.7.0",
+    "@types/node": "^24.3.0",
+    "@types/shelljs": "^0.8.17",
+    "babel-jest": "^29.7.0",
+    "core-js": "~3.42.0",
+    "diff": "^8.0.2",
+    "eslint": "^9.28.0",
+    "expect": "^29.7.0",
+    "globals": "^16.3.0",
+    "jest": "^29.7.0"
+  },
+  "dependencies": {},
+  "scripts": {
+    "lint": "corepack pnpm eslint .",
+    "test": "corepack pnpm jest",
+    "watch": "corepack pnpm jest --watch",
+    "format": "corepack pnpm prettier -w ."
+  },
+  "packageManager": "pnpm@9.15.2"
+}

exercises/practice/prism/prism.js

@@ -0,0 +1,8 @@
+//
+// This is only a SKELETON file for the 'Prism' exercise. It's been provided as a
+// convenience to get you started writing code faster.
+//
+
+export const findSequence = () => {
+  throw new Error('Remove this line and implement the function');
+};