chore: setup linting for Typescript code to ensure consistent style

.editorconfig

@@ -0,0 +1,13 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 120
+
+[*.md]
+trim_trailing_whitespace = false

.github/workflows/test.yml

@@ -26,6 +26,9 @@ jobs:
       - name: Install dependencies
         run: yarn
 
+      - name: Check formatting
+        run: yarn format:check
+
       - name: Check for circular dependencies and print porting order
         run: |
           python3 analyze_imports.py modules

.prettierignore

@@ -0,0 +1,25 @@
+dist/
+build/
+node_modules/
+coverage/
+.yarn/
+.pytest_cache/
+debug-scripts/
+yarn.lock
+package-lock.json
+
+# Generated/data JSON (treat as fixtures, not code)
+tests/**/*.json
+
+# Website build output
+website/build/
+website/.docusaurus/
+
+# Auto-generated docs
+docs/api-reference/
+
+# Other languages / non-JS files
+*.py
+*.rs
+*.md
+*.parquet

.prettierrc.json

@@ -0,0 +1,12 @@
+{
+  "printWidth": 120,
+  "tabWidth": 2,
+  "useTabs": false,
+  "semi": true,
+  "singleQuote": true,
+  "quoteProps": "as-needed",
+  "trailingComma": "none",
+  "bracketSpacing": false,
+  "arrowParens": "avoid",
+  "endOfLine": "lf"
+}

.zed/settings.json

@@ -0,0 +1,38 @@
+{
+  "format_on_save": "on",
+  "formatter": {
+    "external": {
+      "command": "node_modules/.bin/prettier",
+      "arguments": ["--stdin-filepath", "{buffer_path}"]
+    }
+  },
+  "languages": {
+    "TypeScript": {
+      "format_on_save": "on",
+      "formatter": {
+        "external": {
+          "command": "node_modules/.bin/prettier",
+          "arguments": ["--stdin-filepath", "{buffer_path}"]
+        }
+      }
+    },
+    "JavaScript": {
+      "format_on_save": "on",
+      "formatter": {
+        "external": {
+          "command": "node_modules/.bin/prettier",
+          "arguments": ["--stdin-filepath", "{buffer_path}"]
+        }
+      }
+    },
+    "JSON": {
+      "format_on_save": "on",
+      "formatter": {
+        "external": {
+          "command": "node_modules/.bin/prettier",
+          "arguments": ["--stdin-filepath", "{buffer_path}"]
+        }
+      }
+    }
+  }
+}

CONTRIBUTING.md

@@ -23,6 +23,15 @@ yarn test --run
 yarn build
 ```
 
+## Formatting
+
+This project uses [Prettier](https://prettier.io/) for code formatting. The config in `.prettierrc.json` is the source of truth; editors that respect Prettier (Zed, VS Code, JetBrains, vim plugins) will pick it up automatically.
+
+```bash
+yarn format         # format all files in place
+yarn format:check   # exit non-zero if any file would be reformatted (CI use)
+```
+
 ## Generate fixtures
 
 ```bash

docs/table-of-contents.json

@@ -2,10 +2,7 @@
   {
     "type": "category",
     "label": "Overview",
-    "items": [
-      "README",
-      "motivation"
-    ]
+    "items": ["README", "motivation"]
   },
   {
     "type": "category",
@@ -21,11 +18,7 @@
   {
     "type": "category",
     "label": "Recipes",
-    "items": [
-      "recipes/README",
-      "recipes/a5-vs-h3",
-      "recipes/paris-restaurant-density"
-    ]
+    "items": ["recipes/README", "recipes/a5-vs-h3", "recipes/paris-restaurant-density"]
   },
   {
     "type": "category",
@@ -53,10 +46,6 @@
   {
     "type": "category",
     "label": "Ecosystem",
-    "items": [
-      "ecosystem/README",
-      "ecosystem/podcasts-and-talks",
-      "ecosystem/polyglot-mirroring"
-    ]
+    "items": ["ecosystem/README", "ecosystem/podcasts-and-talks", "ecosystem/polyglot-mirroring"]
   }
 ]

examples/cli/aggregate/index.js

@@ -1,5 +1,5 @@
-const { parse } = require('csv-parse/sync');
-const { lonLatToCell, cellToLonLat, u64ToHex } = require('../../../dist/a5.cjs');
+const {parse} = require('csv-parse/sync');
+const {lonLatToCell, cellToLonLat, u64ToHex} = require('../../../dist/a5.cjs');
 const fs = require('fs');
 
 // Read and parse the CSV file
@@ -22,7 +22,7 @@ if (outputFormat !== 'json' && outputFormat !== 'parquet') {
 
 async function writeParquet(aggregatedData, outputPath) {
   // Import parquet writer functions
-  const { parquetWrite, schemaFromColumnData, fileWriter } = await import('hyparquet-writer');
+  const {parquetWrite, schemaFromColumnData, fileWriter} = await import('hyparquet-writer');
 
   // Prepare data arrays
   const cellIds = [];
@@ -35,8 +35,8 @@ async function writeParquet(aggregatedData, outputPath) {
   }
 
   const columnData = [
-    { name: 'a5', data: cellIds },
-    { name: 'count', data: counts }
+    {name: 'a5', data: cellIds},
+    {name: 'count', data: counts}
   ];
 
   // Create file writer
@@ -53,10 +53,10 @@ async function writeParquet(aggregatedData, outputPath) {
           name: 'a5',
           type: 'INT64',
           converted_type: 'UINT_64',
-          repetition_type: 'REQUIRED',
-        },
-      },
-    }),
+          repetition_type: 'REQUIRED'
+        }
+      }
+    })
   });
 
   const fileSize = fs.statSync(outputPath).size;
@@ -98,7 +98,9 @@ async function main() {
       }
     }
 
-    console.log(`Successfully processed ${records.length} points into ${aggregatedData.size} A5 cells at resolution ${resolution}`);
+    console.log(
+      `Successfully processed ${records.length} points into ${aggregatedData.size} A5 cells at resolution ${resolution}`
+    );
 
     // Write output in requested format
     if (outputFormat === 'parquet') {
@@ -110,11 +112,10 @@ async function main() {
       fs.writeFileSync(outputFile, JSON.stringify(result, null, 2));
       console.log(`Output written to ${outputFile}`);
     }
-
   } catch (error) {
     console.error('Error processing data:', error);
     process.exit(1);
   }
 }
 
-main(); 
+main();

examples/cli/compact/index.js

@@ -50,8 +50,13 @@ function parseArgs() {
   }
 
   // Validate required arguments
-  if (options.lon === null || options.lat === null || options.radius === null ||
-    options.resolution === null || !options.output) {
+  if (
+    options.lon === null ||
+    options.lat === null ||
+    options.radius === null ||
+    options.resolution === null ||
+    !options.output
+  ) {
     console.error('Error: Missing required arguments\n');
     printUsage();
     process.exit(1);
@@ -97,7 +102,7 @@ function generatePointsInRadius(centerLonLat, radiusKm, spacingMeters) {
   // Convert radius to approximate degrees
   // At the given latitude, calculate degrees per km
   const latDegreesPerKm = 1 / 111;
-  const lonDegreesPerKm = 1 / (111 * Math.cos(centerLat * Math.PI / 180));
+  const lonDegreesPerKm = 1 / (111 * Math.cos((centerLat * Math.PI) / 180));
 
   const radiusDegLat = radiusKm * latDegreesPerKm;
   const radiusDegLon = radiusKm * lonDegreesPerKm;
@@ -121,10 +126,7 @@ function generatePointsInRadius(centerLonLat, radiusKm, spacingMeters) {
       // Check if point is within radius (simple Euclidean approximation)
       const dLat = lat - centerLat;
       const dLon = lon - centerLon;
-      const distKm = Math.sqrt(
-        (dLat / latDegreesPerKm) ** 2 +
-        (dLon / lonDegreesPerKm) ** 2
-      );
+      const distKm = Math.sqrt((dLat / latDegreesPerKm) ** 2 + (dLon / lonDegreesPerKm) ** 2);
 
       if (distKm <= radiusKm) {
         points.push([lon, lat]);
@@ -169,7 +171,7 @@ function generateCells(centerLonLat, radiusKm, resolution) {
   console.log(`  Compacted to: ${compacted.length} cells`);
   console.log(`  Compression ratio: ${(cells.length / compacted.length).toFixed(2)}x`);
 
-  return { uncompacted: cells, compacted };
+  return {uncompacted: cells, compacted};
 }
 
 /**
@@ -179,14 +181,12 @@ async function writeParquet(cells, outputPath) {
   const parquetPath = `${outputPath}.parquet`;
 
   // Ensure all values are BigInt (some might be plain numbers)
-  const cellIds = cells.map(id => typeof id === 'bigint' ? id : BigInt(id));
+  const cellIds = cells.map(id => (typeof id === 'bigint' ? id : BigInt(id)));
 
   // Import parquet writer functions
-  const { ByteWriter, parquetWrite, schemaFromColumnData, fileWriter } = await import('hyparquet-writer');
+  const {ByteWriter, parquetWrite, schemaFromColumnData, fileWriter} = await import('hyparquet-writer');
 
-  const columnData = [
-    { name: 'cell_id', data: cellIds }
-  ];
+  const columnData = [{name: 'cell_id', data: cellIds}];
 
   // Create file writer
   const writer = fileWriter(parquetPath);
@@ -203,10 +203,10 @@ async function writeParquet(cells, outputPath) {
           name: 'cell_id',
           type: 'INT64',
           converted_type: 'UINT_64',
-          repetition_type: 'REQUIRED',
-        },
-      },
-    }),
+          repetition_type: 'REQUIRED'
+        }
+      }
+    })
   });
 
   const fileSize = fs.statSync(parquetPath).size;
@@ -227,7 +227,7 @@ function writeGeoJSON(cells, outputPath) {
     const cellIdHex = u64ToHex(cellId);
     const boundary = cellToBoundary(cellId, {
       closedRing: true,
-      segments: 10,
+      segments: 10
     });
 
     features.push({
@@ -242,7 +242,7 @@ function writeGeoJSON(cells, outputPath) {
 
   const geojson = {
     type: 'FeatureCollection',
-    features,
+    features
   };
 
   fs.writeFileSync(geojsonPath, JSON.stringify(geojson, null, 2));
@@ -261,11 +261,7 @@ async function main() {
     console.log(`  Resolution: ${options.resolution}\n`);
 
     // Generate cells (both uncompacted and compacted)
-    const { uncompacted, compacted } = generateCells(
-      [options.lon, options.lat],
-      options.radius,
-      options.resolution
-    );
+    const {uncompacted, compacted} = generateCells([options.lon, options.lat], options.radius, options.resolution);
 
     // Choose which cells to output
     const cellsToOutput = options.uncompacted ? uncompacted : compacted;
@@ -279,7 +275,6 @@ async function main() {
     }
 
     console.log('\n✓ Generation complete!');
-
   } catch (error) {
     console.error('Error:', error.message);
     process.exit(1);

examples/cli/country-polygons/index.js

@@ -18,7 +18,9 @@ function parseArgs() {
     else if (a === '--output') opts.output = args[++i];
     else if (a === '--resolution') opts.resolution = parseInt(args[++i]);
     else if (a === '--help' || a === '-h') {
-      console.log(`Usage: node index.js [--input <geojson>] [--output <parquet>] [--resolution <n>]\n\nDefaults:\n  --input ${DEFAULT_INPUT}\n  --output ${DEFAULT_OUTPUT}\n  --resolution ${DEFAULT_RESOLUTION}\n`);
+      console.log(
+        `Usage: node index.js [--input <geojson>] [--output <parquet>] [--resolution <n>]\n\nDefaults:\n  --input ${DEFAULT_INPUT}\n  --output ${DEFAULT_OUTPUT}\n  --resolution ${DEFAULT_RESOLUTION}\n`
+      );
       process.exit(0);
     } else {
       console.error(`Unknown option: ${a}`);
@@ -90,7 +92,7 @@ async function main() {
   const {parquetWrite, schemaFromColumnData, fileWriter} = await import('hyparquet-writer');
   const columnData = [
     {name: 'cell_id', data: cellIds},
-    {name: 'color', data: colors},
+    {name: 'color', data: colors}
   ];
   const writer = fileWriter(opts.output);
   parquetWrite({
@@ -99,9 +101,9 @@ async function main() {
     schema: schemaFromColumnData({
       columnData,
       schemaOverrides: {
-        cell_id: {name: 'cell_id', type: 'INT64', converted_type: 'UINT_64', repetition_type: 'REQUIRED'},
-      },
-    }),
+        cell_id: {name: 'cell_id', type: 'INT64', converted_type: 'UINT_64', repetition_type: 'REQUIRED'}
+      }
+    })
   });
 
   const size = fs.statSync(opts.output).size;