Merge a45870de45703a332153c961f7ff3b667b712ee1 into 4fe9a60a0c9da952dadc5214a9ca5c68c447fdf8

.eslintrc.cjs

@@ -1,16 +1,17 @@
 module.exports = {
     "env": {
-        "es6": true,
         "node": true,
+        "es2021": true,
         "jest": true
     },
-    "parserOptions": {
-        "ecmaVersion": 2018
-    },
     "extends": [
         "eslint:recommended",
         "plugin:jest/recommended"
     ],
+    "parserOptions": {
+        "ecmaVersion": "latest",
+        "sourceType": "module"
+    },
     "rules": {
         "indent": [
             "error",
@@ -33,4 +34,4 @@ module.exports = {
             "always"
         ]
     }
-};
+}

main.js

@@ -7,11 +7,11 @@
 
   TODO: params parsing and so on
 #*/
-'use strict';
-const config = require('./src/config');
-const Mapscii = require('./src/Mapscii');
-const argv = require('yargs')
-  .option('latitude', {
+import config from './src/config.js';
+import Mapscii from './src/Mapscii.js';
+import yargs from 'yargs';
+
+const argv = yargs().option('latitude', {
     alias: 'lat',
     description: 'Latitude of initial centre',
     default: config.initialLat,

package.json

@@ -3,10 +3,11 @@
   "version": "0.3.1",
   "description": "MapSCII is a Braille & ASCII world map renderer for your console, based on OpenStreetMap",
   "main": "main.js",
+  "type": "module",
   "scripts": {
     "lint": "eslint src",
     "start": "node main",
-    "test": "jest"
+    "test": "NODE_OPTIONS=--experimental-vm-modules jest"
   },
   "repository": {
     "type": "git",
@@ -32,21 +33,21 @@
   "dependencies": {
     "@mapbox/vector-tile": "^1.3.1",
     "bresenham": "0.0.4",
-    "earcut": "^2.2.2",
-    "env-paths": "^2.2.0",
+    "earcut": "^2.2.4",
+    "env-paths": "^3.0.0",
     "keypress": "^0.2.1",
-    "node-fetch": "^2.6.1",
+    "node-fetch": "^3.3.0",
     "pbf": "^3.2.1",
     "rbush": "^3.0.1",
     "simplify-js": "^1.2.4",
-    "string-width": "^4.2.0",
+    "string-width": "^5.1.2",
     "term-mouse": "^0.2.2",
     "x256": "0.0.2",
-    "yargs": "^15.4.1"
+    "yargs": "^17.7.1"
   },
   "devDependencies": {
-    "eslint": "^7.8.1",
-    "eslint-plugin-jest": "^24.0.0",
-    "jest": "^26.4.2"
+    "eslint": "^8.35.0",
+    "eslint-plugin-jest": "^27.2.1",
+    "jest": "^29.4.3"
   }
 }

src/BrailleBuffer.js

@@ -11,10 +11,9 @@
 
   Will either be merged into node-drawille or become an own module at some point
 */
-'use strict';
-const stringWidth = require('string-width');
-const config = require('./config');
-const utils = require('./utils');
+import stringWidth from 'string-width';
+import config from './config.js';
+import * as utils from './utils.js';
 
 const asciiMap = {
   // '▬': [2+32, 4+64],
@@ -29,7 +28,7 @@ const asciiMap = {
 };
 const termReset = '\x1B[39;49m';
 
-class BrailleBuffer {
+export default class BrailleBuffer {
   constructor(width, height) {
     this.brailleMap = [[0x1, 0x8],[0x2, 0x10],[0x4, 0x20],[0x40, 0x80]];
 
@@ -114,9 +113,8 @@ class BrailleBuffer {
     }
 
     //TODO Optimize this part
-    var i, k;
     const results = [];
-    for (i = k = 1; k <= 255; i = ++k) {
+    for (let i = 1; i <= 255; i++) {
       const braille = (i & 7) + ((i & 56) << 1) + ((i & 64) >> 3) + (i & 128);
       results.push(this.asciiToBraille[i] = masks.reduce((function(best, mask) {
         const covered = utils.population(mask.mask & braille);
@@ -207,5 +205,3 @@ class BrailleBuffer {
     }
   }
 }
-
-module.exports = BrailleBuffer;

src/BrailleBuffer.spec.js

@@ -0,0 +1,10 @@
+import BrailleBuffer from './BrailleBuffer.js';
+
+const termReset = '\x1B[39;49m';
+
+describe('BrailleBuffer', () => {
+  test('starts a frame with term reset characters', async () => {
+    const brailleBuffer = new BrailleBuffer(1, 1);
+    expect(brailleBuffer.frame().startsWith(termReset)).toBe(true);
+  });
+});

src/Canvas.js

@@ -10,12 +10,11 @@
 
   Will most likely be turned into a stand alone module at some point
  */
-'use strict';
-const bresenham = require('bresenham');
-const earcut = require('earcut');
-const BrailleBuffer = require('./BrailleBuffer');
+import bresenham from 'bresenham';
+import earcut from 'earcut';
+import BrailleBuffer from './BrailleBuffer.js';
 
-class Canvas {
+export default class Canvas {
   constructor(width, height) {
     this.width = width;
     this.height = height;
@@ -164,9 +163,8 @@ class Canvas {
     const b = this._bresenham(pointA, pointC);
     const c = this._bresenham(pointA, pointB);
     
-    const points = a.concat(b).concat(c).filter((point) => {
-      var ref;
-      return (0 <= (ref = point.y) && ref < this.height);
+    const points = a.concat(b).concat(c).filter(({y}) => {
+      return 0 <= y && y < this.height;
     }).sort(function(a, b) {
       if (a.y === b.y) {
         return a.x - b.x;
@@ -198,5 +196,3 @@ class Canvas {
 }
 
 Canvas.prototype.stack = [];
-
-module.exports = Canvas;

src/LabelBuffer.js

@@ -5,11 +5,10 @@
   Using 2D spatial indexing to avoid overlapping labels and markers
   and to find labels underneath a mouse cursor's position
 */
-'use strict';
-const RBush = require('rbush');
-const stringWidth = require('string-width');
+import RBush from 'rbush';
+import stringWidth from 'string-width';
 
-module.exports = class LabelBuffer {
+export default class LabelBuffer {
 
   constructor() {
     this.tree = new RBush();
@@ -54,4 +53,4 @@ module.exports = class LabelBuffer {
       maxY: y+margin/2,
     };
   }
-};
+}

src/Mapscii.js

@@ -4,17 +4,16 @@
 
   UI and central command center
 */
-'use strict';
-const fs = require('fs');
-const keypress = require('keypress');
-const TermMouse = require('term-mouse');
+import fsPromises from 'fs/promises';
+import keypress from 'keypress';
+import TermMouse from 'term-mouse';
 
-const Renderer = require('./Renderer');
-const TileSource = require('./TileSource');
-const utils = require('./utils');
-let config = require('./config');
+import Renderer from './Renderer.js';
+import TileSource from './TileSource.js';
+import * as utils from './utils.js';
+import MapsciiConfig from './config.js';
 
-class Mapscii {
+export default class Mapscii {
   constructor(options) {
     this.width = null;
     this.height = null;
@@ -32,45 +31,48 @@ class Mapscii {
 
     this.zoom = 0;
     this.minZoom = null;
-    config = Object.assign(config, options);
+    this.config = {
+      ...MapsciiConfig,
+      ...options,
+    };
 
     this.center = {
-      lat: config.initialLat,
-      lon: config.initialLon
+      lat: this.config.initialLat,
+      lon: this.config.initialLon,
     };
   }
 
   async init() {
-    if (!config.headless) {
+    if (!this.config.headless) {
       this._initKeyboard();
       this._initMouse();
     }
-    this._initTileSource();
-    this._initRenderer();
-    this._draw();
+    await this._initTileSource();
+    await this._initRenderer();
+    await this._draw();
     this.notify('Welcome to MapSCII! Use your cursors to navigate, a/z to zoom, q to quit.');
   }
 
 
-  _initTileSource() {
+  async _initTileSource() {
     this.tileSource = new TileSource();
-    this.tileSource.init(config.source);
+    await this.tileSource.init(this.config.source);
   }
 
   _initKeyboard() {
-    keypress(config.input);
-    if (config.input.setRawMode) {
-      config.input.setRawMode(true);
+    keypress(this.config.input);
+    if (this.config.input.setRawMode) {
+      this.config.input.setRawMode(true);
     }
-    config.input.resume();
+    this.config.input.resume();
 
-    config.input.on('keypress', (ch, key) => this._onKey(key));
+    this.config.input.on('keypress', (ch, key) => this._onKey(key));
   }
 
   _initMouse() {
     this.mouse = TermMouse({
-      input: config.input,
-      output: config.output,
+      input: this.config.input,
+      output: this.config.output,
     });
     this.mouse.start();
 
@@ -79,22 +81,22 @@ class Mapscii {
     this.mouse.on('move', (event) => this._onMouseMove(event));
   }
 
-  _initRenderer() {
-    const style = JSON.parse(fs.readFileSync(config.styleFile, 'utf8'));
-    this.renderer = new Renderer(config.output, this.tileSource, style);
+  async _initRenderer() {
+    const style = JSON.parse(await fsPromises.readFile(this.config.styleFile, 'utf8'));
+    this.renderer = new Renderer(this.tileSource, style);
 
-    config.output.on('resize', () => {
+    this.config.output.on('resize', () => {
       this._resizeRenderer();
       this._draw();
     });
 
     this._resizeRenderer();
-    this.zoom = (config.initialZoom !== null) ? config.initialZoom : this.minZoom;
+    this.zoom = (this.config.initialZoom !== null) ? this.config.initialZoom : this.minZoom;
   }
 
   _resizeRenderer() {
-    this.width = config.size && config.size.width ? config.size.width * 2 : config.output.columns >> 1 << 2;
-    this.height = config.size && config.size.height ? config.size.height * 4 : config.output.rows * 4 - 4;
+    this.width = this.config.size && this.config.size.width ? this.config.size.width * 2 : this.config.output.columns >> 1 << 2;
+    this.height = this.config.size && this.config.size.height ? this.config.size.height * 4 : this.config.output.rows * 4 - 4;
 
     this.minZoom = 4-Math.log(4096/this.width)/Math.LN2;
 
@@ -142,7 +144,7 @@ class Mapscii {
     const targetMouseLonLat = this._colrow2ll(event.x, event.y);
 
     // zoom toward the center
-    this.zoomBy(config.zoomStep * (event.button === 'up' ? 1 : -1));
+    this.zoomBy(this.config.zoomStep * (event.button === 'up' ? 1 : -1));
 
     // the location the pointer ended up after zooming
     const offsetMouseLonLat = this._colrow2ll(event.x, event.y);
@@ -171,7 +173,7 @@ class Mapscii {
     if (event.x < 0 || event.x > this.width/2 || event.y < 0 || event.y > this.height/4) {
       return;
     }
-    if (config.mouseCallback && !config.mouseCallback(event)) {
+    if (this.config.mouseCallback && !this.config.mouseCallback(event)) {
       return;
     }
 
@@ -207,25 +209,25 @@ class Mapscii {
   }
 
   _onKey(key) {
-    if (config.keyCallback && !config.keyCallback(key)) return;
+    if (this.config.keyCallback && !this.config.keyCallback(key)) return;
     if (!key || !key.name) return;
 
     // check if the pressed key is configured
     let draw = true;
     switch (key.name) {
       case 'q':
-        if (config.quitCallback) {
-          config.quitCallback();
+        if (this.config.quitCallback) {
+          this.config.quitCallback();
         } else {
           process.exit(0);
         }
         break;
       case 'a':
-        this.zoomBy(config.zoomStep);
+        this.zoomBy(this.config.zoomStep);
         break;
       case 'y':
       case 'z':
-        this.zoomBy(-config.zoomStep);
+        this.zoomBy(-this.config.zoomStep);
         break;
       case 'left':
       case 'h':
@@ -244,7 +246,7 @@ class Mapscii {
         this.moveBy(-6/Math.pow(2, this.zoom), 0);
         break;
       case 'c':
-        config.useBraille = !config.useBraille;
+        this.config.useBraille = !this.config.useBraille;
         break;
       default:
         draw = false;
@@ -255,13 +257,14 @@ class Mapscii {
     }
   }
 
-  _draw() {
-    this.renderer.draw(this.center, this.zoom).then((frame) => {
+  async _draw() {
+    try {
+      const frame = await this.renderer.draw(this.center, this.zoom);
       this._write(frame);
       this.notify(this._getFooter());
-    }).catch(() => {
+    } catch {
       this.notify('renderer is busy');
-    });
+    }
   }
 
   _getFooter() {
@@ -277,22 +280,22 @@ class Mapscii {
   }
 
   notify(text) {
-    config.onUpdate && config.onUpdate();
-    if (!config.headless) {
+    this.config.onUpdate && this.config.onUpdate();
+    if (!this.config.headless) {
       this._write('\r\x1B[K' + text);
     }
   }
 
   _write(output) {
-    config.output.write(output);
+    this.config.output.write(output);
   }
 
   zoomBy(step) {
     if (this.zoom+step < this.minZoom) {
       return this.zoom = this.minZoom;
     }
-    if (this.zoom+step > config.maxZoom) {
-      return this.zoom = config.maxZoom;
+    if (this.zoom+step > this.config.maxZoom) {
+      return this.zoom = this.config.maxZoom;
     }
 
     this.zoom += step;
@@ -309,5 +312,3 @@ class Mapscii {
     });
   }
 }
-
-module.exports = Mapscii;

src/Renderer.js

@@ -4,19 +4,17 @@
 
   The Console Vector Tile renderer - bäm!
 */
-'use strict';
-const x256 = require('x256');
-const simplify = require('simplify-js');
+import x256 from 'x256';
+import simplify from 'simplify-js';
 
-const Canvas = require('./Canvas');
-const LabelBuffer = require('./LabelBuffer');
-const Styler = require('./Styler');
-const utils = require('./utils');
-const config = require('./config');
+import Canvas from './Canvas.js';
+import LabelBuffer from './LabelBuffer.js';
+import Styler from './Styler.js';
+import * as utils from './utils.js';
+import config from './config.js';
 
-class Renderer {
-  constructor(output, tileSource, style) {
-    this.output = output;
+export default class Renderer {
+  constructor(tileSource, style) {
     this.tileSource = tileSource;
     this.labelBuffer = new LabelBuffer();
     this.styler = new Styler(style);
@@ -331,5 +329,3 @@ Renderer.prototype.lastDrawAt = 0;
 Renderer.prototype.labelBuffer = null;
 Renderer.prototype.tileSource = null;
 Renderer.prototype.tilePadding = 64;
-
-module.exports = Renderer;

src/Renderer.spec.js

@@ -0,0 +1,21 @@
+import fsPromises from 'fs/promises';
+import Renderer from './Renderer';
+import TileSource from './TileSource.js';
+
+const center = {
+  lat: 52.51298,
+  lon: 13.42012,
+};
+
+describe('Renderer', () => {
+  describe('with a HTTP source', () => {
+    test('does not crash when creating a Renderer', async () => {
+      const tileSource = new TileSource();
+      await tileSource.init('http://mapscii.me/');
+      const style = JSON.parse(await fsPromises.readFile('./styles/dark.json'));
+      const renderer = new Renderer(tileSource, style);
+      renderer.setSize(30, 30);
+      expect(await renderer.draw(center, 13)).toMatchSnapshot();
+    });
+  });
+});

src/Styler.js

@@ -8,13 +8,11 @@
   Compiles layer filter instructions into a chain of true/false returning
   anonymous functions to improve rendering speed compared to realtime parsing.
 */
-'use strict';
 
-class Styler {
+export default class Styler {
   constructor(style) {
     this.styleById = {};
     this.styleByLayer = {};
-    var base, name;
     this.styleName = style.name;
     if (style.constants) {
       this._replaceConstants(style.constants, style.layers);
@@ -31,10 +29,7 @@ class Styler {
 
       layer.appliesTo = this._compileFilter(layer.filter);
 
-      //TODO Better translation of: @styleByLayer[style['source-layer']] ?= []
-      if ((base = this.styleByLayer)[name = layer['source-layer']] == null) {
-        base[name] = [];
-      }
+      this.styleByLayer[layer['source-layer']] ??= [];
       this.styleByLayer[layer['source-layer']].push(layer);
       this.styleById[layer.id] = layer;
     }
@@ -129,5 +124,3 @@ class Styler {
     }
   }
 }
-
-module.exports = Styler;

src/Styler.spec.js

@@ -0,0 +1,12 @@
+import fsPromises from 'fs/promises';
+import Styler from './Styler';
+
+describe('Styler', () => {
+  describe('getStyleFor', () => {
+    test('returns false for landuse_park, line', async () => {
+      const style = JSON.parse(await fsPromises.readFile('./styles/dark.json'));
+      const styler = new Styler(style);
+      expect(styler.getStyleFor('landuse_park', 'line')).toBe(false);
+    });
+  });
+});

src/Tile.js

@@ -4,29 +4,24 @@
 
   Handling of and access to single VectorTiles
 */
-'use strict';
-const VectorTile = require('@mapbox/vector-tile').VectorTile;
-const Protobuf = require('pbf');
-const zlib = require('zlib');
-const RBush = require('rbush');
-const x256 = require('x256');
+import { VectorTile } from '@mapbox/vector-tile';
+import Protobuf from 'pbf';
+import zlib from 'zlib';
+import RBush from 'rbush';
+import x256 from 'x256';
 
-const config = require('./config');
-const utils = require('./utils');
+import config from './config.js';
+import * as utils from './utils.js';
 
-class Tile {
+export default class Tile {
   constructor(styler) {
     this.styler = styler;
   }
 
-  load(buffer) {
-    return this._unzipIfNeeded(buffer).then((buffer) => {
-      return this._loadTile(buffer);
-    }).then(() => {
-      return this._loadLayers();
-    }).then(() => {
-      return this;
-    });
+  async load(buffer) {
+    const unzippedBuffer = await this._unzipIfNeeded(buffer);
+    this._loadTile(unzippedBuffer);
+    this._loadLayers();
   }
 
   _loadTile(buffer) {
@@ -122,10 +117,10 @@ class Tile {
   }
 
   _addBoundaries(deep, data) {
-    let minX = 2e308;
-    let maxX = -2e308;
-    let minY = 2e308;
-    let maxY = -2e308;
+    let minX = 2e307;
+    let maxX = -2e307;
+    let minY = 2e307;
+    let maxY = -2e307;
     const points = (deep ? data.points[0] : data.points);
     for (const p of points) {
       if (p.x < minX) minX = p.x;
@@ -163,5 +158,3 @@ class Tile {
 }
 
 Tile.prototype.layers = {};
-
-module.exports = Tile;

src/TileSource.js

@@ -6,15 +6,14 @@
   * remote TileServer
   * local MBTiles and VectorTiles
 */
-'use strict';
-const fs = require('fs');
-const path = require('path');
-const fetch = require('node-fetch');
-const envPaths = require('env-paths');
+import fsPromises from 'fs/promises';
+import path from 'path';
+import fetch from 'node-fetch';
+import envPaths from 'env-paths';
 const paths = envPaths('mapscii');
 
-const Tile = require('./Tile');
-const config = require('./config');
+import Tile from './Tile.js';
+import config from './config.js';
 
 // https://github.com/mapbox/node-mbtiles has native build dependencies (sqlite3)
 // To maximize MapSCII’s compatibility, MBTiles support must be manually added via
@@ -30,8 +29,8 @@ const modes = {
   HTTP: 3,
 };
 
-class TileSource {
-  init(source) {
+export default class TileSource {
+  async init(source) {
     this.source = source;
     
     this.cache = {};
@@ -44,7 +43,7 @@ class TileSource {
     
     if (this.source.startsWith('http')) {
       if (config.persistDownloadedTiles) {
-        this._initPersistence();
+        await this._initPersistence();
       }
 
       this.mode = modes.HTTP;
@@ -102,15 +101,16 @@ class TileSource {
     }
   }
 
-  _getHTTP(z, x, y) {
+  async _getHTTP(z, x, y) {
     let promise;
-    const persistedTile = this._getPersited(z, x, y);
+    const persistedTile = await this._getPersited(z, x, y);
     if (config.persistDownloadedTiles && persistedTile) {
       promise = Promise.resolve(persistedTile);
     } else {
       promise = fetch(this.source + [z,x,y].join('/') + '.pbf')
-        .then((res) => res.buffer())
-        .then((buffer) => {
+        .then((res) => res.arrayBuffer())
+        .then((arrayBuffer) => {
+          const buffer = Buffer.from(arrayBuffer);
           if (config.persistDownloadedTiles) {
             this._persistTile(z, x, y, buffer);
             return buffer;
@@ -122,7 +122,7 @@ class TileSource {
     });
   }
 
-  _getMBTile(z, x, y) {
+  async _getMBTile(z, x, y) {
     return new Promise((resolve, reject) => {
       this.mbtiles.getTile(z, x, y, (err, buffer) => {
         if (err) {
@@ -133,40 +133,41 @@ class TileSource {
     });
   }
 
-  _createTile(z, x, y, buffer) {
+  async _createTile(z, x, y, buffer) {
     const name = [z, x, y].join('-');
     this.cached.push(name);
     
     const tile = this.cache[name] = new Tile(this.styler);
-    return tile.load(buffer);
+    await tile.load(buffer);
+    return tile;
   }
 
-  _initPersistence() {
+  async _initPersistence() {
     try {
-      this._createFolder(paths.cache);
+      await this._createFolder(paths.cache);
     } catch (error) {
       config.persistDownloadedTiles = false;
     }
   }
 
-  _persistTile(z, x, y, buffer) {
+  async _persistTile(z, x, y, buffer) {
     const zoom = z.toString();
-    this._createFolder(path.join(paths.cache, zoom));
+    await this._createFolder(path.join(paths.cache, zoom));
     const filePath = path.join(paths.cache, zoom, `${x}-${y}.pbf`);
-    return fs.writeFile(filePath, buffer, () => null);
+    return fsPromises.writeFile(filePath, buffer);
   }
 
-  _getPersited(z, x, y) {
+  async _getPersited(z, x, y) {
     try {
-      return fs.readFileSync(path.join(paths.cache, z.toString(), `${x}-${y}.pbf`));
+      return await fsPromises.readFile(path.join(paths.cache, z.toString(), `${x}-${y}.pbf`));
     } catch (error) {
       return false;
     }
   }
 
-  _createFolder(path) {
+  async _createFolder(path) {
     try {
-      fs.mkdirSync(path);
+      await fsPromises.mkdir(path);
       return true;
     } catch (error) {
       if (error.code === 'EEXIST') return true;
@@ -174,5 +175,3 @@ class TileSource {
     }
   }
 }
-
-module.exports = TileSource;

src/TileSource.spec.js

@@ -1,5 +1,4 @@
-'use strict';
-const TileSource = require('./TileSource');
+import TileSource from './TileSource.js';
 
 describe('TileSource', () => {
   describe('with a HTTP source', () => {

src/config.js

@@ -1,4 +1,10 @@
-module.exports = {
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+export default {
   language: 'en',
 
   // TODO: adapt to osm2vectortiles successor openmaptiles v3)
@@ -7,7 +13,7 @@ module.exports = {
 
   //source: __dirname+"/../mbtiles/regensburg.mbtiles",
 
-  styleFile: __dirname+'/../styles/dark.json',
+  styleFile: __dirname + '/../styles/dark.json',
 
   initialZoom: null,
   maxZoom: 18,

src/utils.js

@@ -4,15 +4,13 @@
 
   methods used all around
 */
-'use strict';
-const config = require('./config');
+import config from './config.js';
 
 const constants = {
   RADIUS: 6378137,
 };
 
-const utils = {
-  clamp: (num, min, max) => {
+export const clamp = (num, min, max) => {
   if (num <= min) {
     return min;
   } else if (num >= max) {
@@ -20,43 +18,43 @@ const utils = {
   } else {
     return num;
   }
-  },
+};
 
-  baseZoom: (zoom) => {
+export const baseZoom = (zoom) => {
   return Math.min(config.tileRange, Math.max(0, Math.floor(zoom)));
-  },
+};
 
-  tilesizeAtZoom: (zoom) => {
-    return config.projectSize * Math.pow(2, zoom-utils.baseZoom(zoom));
-  },
+export const tilesizeAtZoom = (zoom) => {
+  return config.projectSize * Math.pow(2, zoom-baseZoom(zoom));
+};
 
-  deg2rad: (angle) => {
+export const deg2rad = (angle) => {
   // (angle / 180) * Math.PI
   return angle * 0.017453292519943295;
-  },
+};
 
-  ll2tile: (lon, lat, zoom) => {
+export const ll2tile = (lon, lat, zoom) => {
   return {
     x: (lon+180)/360*Math.pow(2, zoom),
     y: (1-Math.log(Math.tan(lat*Math.PI/180)+1/Math.cos(lat*Math.PI/180))/Math.PI)/2*Math.pow(2, zoom),
     z: zoom,
   };
-  },
+};
 
-  tile2ll: (x, y, zoom) => {
+export const tile2ll = (x, y, zoom) => {
   const n = Math.PI - 2*Math.PI*y/Math.pow(2, zoom);
 
   return {
     lon: x/Math.pow(2, zoom)*360-180,
     lat: 180/Math.PI*Math.atan(0.5*(Math.exp(n)-Math.exp(-n))),
   };
-  },
+};
 
-  metersPerPixel: (zoom, lat = 0) => {
+export const metersPerPixel = (zoom, lat = 0) => {
   return (Math.cos(lat * Math.PI/180) * 2 * Math.PI * constants.RADIUS) / (256 * Math.pow(2, zoom));
-  },
+};
 
-  hex2rgb: (color) => {
+export const hex2rgb = (color) => {
   if (typeof color !== 'string') return [255, 0, 0];
 
   if (!/^#[a-fA-F0-9]{3,6}$/.test(color)) {
@@ -74,13 +72,13 @@ const utils = {
   } else {
     return [(decimal>>16)&255, (decimal>>8)&255, decimal&255];
   }
-  },
+};
 
-  digits: (number, digits) => {
-    return Math.floor(number*Math.pow(10, digits))/Math.pow(10, digits);
-  },
+export const digits = (number, digits) => {
+  return (Math.floor(number*Math.pow(10, digits))/Math.pow(10, digits)).toFixed(digits);
+};
 
-  normalize: (ll) => {
+export const normalize = (ll) => {
   if (ll.lon < -180) ll.lon += 360;
   if (ll.lon > 180) ll.lon -= 360;
 
@@ -88,16 +86,13 @@ const utils = {
   if (ll.lat < -85.0511) ll.lat = -85.0511;
 
   return ll;
-  },
+};
 
-  population: (val) => {
+export const population = (val) => {
   let bits = 0;
   while (val > 0) {
     bits += val & 1;
     val >>= 1;
   }
   return bits;
-  },
 };
-
-module.exports = utils;

src/utils.spec.js

@@ -1,7 +1,18 @@
-'use strict';
-const utils = require('./utils');
+import * as utils from './utils.js';
 
 describe('utils', () => {
+  describe('digits', () => {
+    describe.each([
+      [1, 0, '1'],
+      [1, 1, '1.0'],
+      [3.1415, 3, '3.141'],
+    ])('when given value=%f and digits=%f', (value, digits, expected_value) => {
+      test(`returns ${expected_value}`, () => {
+        expect(utils.digits(value, digits)).toEqual(expected_value);
+      });
+    });
+  });
+
   describe('hex2rgb', () => {
     describe.each([
       ['#ff0000', 255, 0, 0],
@@ -22,9 +33,8 @@ describe('utils', () => {
       expect(wrapper).toThrow('isn\'t a supported hex color');
     });
   });
-});
 
-describe('normalize', () => {
+  describe('normalize', () => {
     describe.each([
       [0, 0, 0, 0],
       [61, 48, 61, 48],
@@ -44,4 +54,5 @@ describe('normalize', () => {
         expect(utils.normalize(input)).toEqual(expected);
       });
     });
+  });
 });