New module @turf/clean-coords

packages/turf-clean-coords/LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2017 TurfJS
+
+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.

packages/turf-clean-coords/README.md

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+# @turf/clean-coords
+
+# cleanCoords
+
+Removes redundant coordinates from a (Multi)LineString or (Multi)Polygon; ignores (Multi)Point.
+
+**Parameters**
+
+-   `geojson` **([Geometry](http://geojson.org/geojson-spec.html#geometry) \| [Feature](http://geojson.org/geojson-spec.html#feature-objects)<any>)** Feature or Geometry
+-   `mutate` **\[[boolean](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean)]** allows GeoJSON input to be mutated (optional, default `false`)
+
+**Examples**
+
+```javascript
+var line = trf.lineString([[0, 0], [0, 2], [0, 5], [0, 8], [0, 8], [0, 10]]);
+
+var cleaned = turf.cleanCoords(line).geometry.coordinates;
+//= [[0, 0], [0, 10]]
+```
+
+Returns **([Geometry](http://geojson.org/geojson-spec.html#geometry) \| [Feature](http://geojson.org/geojson-spec.html#feature-objects)<any>)** the cleaned input Feature/Geometry
+
+<!-- This file is automatically generated. Please don't edit it directly:
+if you find an error, edit the source file (likely index.js), and re-run
+./scripts/generate-readmes in the turf project. -->
+
+---
+
+This module is part of the [Turfjs project](http://turfjs.org/), an open source
+module collection dedicated to geographic algorithms. It is maintained in the
+[Turfjs/turf](https://github.com/Turfjs/turf) repository, where you can create
+PRs and issues.
+
+### Installation
+
+Install this module individually:
+
+```sh
+$ npm install @turf/clean-coords
+```
+
+Or install the Turf module that includes it as a function:
+
+```sh
+$ npm install @turf/turf
+```

packages/turf-clean-coords/bench.js

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+const path = require('path');
+const glob = require('glob');
+const load = require('load-json-file');
+const Benchmark = require('benchmark');
+const cleanCoords = require('./');
+
+/**
+ * Benchmark Results
+ *
+ * multiline: 1.030ms
+ * multipoint: 0.078ms
+ * multipolygon: 0.329ms
+ * point: 0.060ms
+ * polygon-with-hole: 0.191ms
+ * polygon: 0.073ms
+ * simple-line: 0.064ms
+ * triangle: 0.105ms
+ * multiline x 86,027 ops/sec ±2.78% (72 runs sampled)
+ * multipoint x 112,741 ops/sec ±3.84% (74 runs sampled)
+ * multipolygon x 49,881 ops/sec ±2.92% (75 runs sampled)
+ * point x 163,172 ops/sec ±6.79% (68 runs sampled)
+ * polygon-with-hole x 67,728 ops/sec ±3.33% (73 runs sampled)
+ * polygon x 111,302 ops/sec ±3.23% (76 runs sampled)
+ * simple-line x 136,383 ops/sec ±2.53% (76 runs sampled)
+ * triangle x 93,747 ops/sec ±3.09% (76 runs sampled)
+ */
+const suite = new Benchmark.Suite('turf-clean-coords');
+glob.sync(path.join(__dirname, 'test', 'in', '*.geojson')).forEach(filepath => {
+    const {name} = path.parse(filepath);
+    const geojson = load.sync(filepath);
+    console.time(name);
+    cleanCoords(geojson);
+    console.timeEnd(name);
+    suite.add(name, () => cleanCoords(geojson));
+});
+
+suite
+    .on('cycle', e => console.log(String(e.target)))
+    .on('complete', () => {})
+    .run();

packages/turf-clean-coords/index.d.ts

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+/// <reference types="geojson" />
+
+type Feature = GeoJSON.Feature<any> | GeoJSON.GeometryObject;
+
+/**
+ * http://turfjs.org/docs/#cleancoords
+ */
+declare function cleanCoords(feature: Feature, mutate?: boolean): Feature;
+declare namespace cleanCoords {}
+export = cleanCoords;

packages/turf-clean-coords/index.js

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+var clone = require('@turf/clone');
+var invariant = require('@turf/invariant');
+var getCoords = invariant.getCoords;
+var getGeomType = invariant.getGeomType;
+
+/**
+ * Removes redundant coordinates from a (Multi)LineString or (Multi)Polygon; ignores (Multi)Point.
+ *
+ * @name cleanCoords
+ * @param {Geometry|Feature} geojson Feature or Geometry
+ * @param {boolean} [mutate=false] allows GeoJSON input to be mutated
+ * @returns {Geometry|Feature} the cleaned input Feature/Geometry
+ * @example
+ * var line = turf.lineString([[0, 0], [0, 2], [0, 5], [0, 8], [0, 8], [0, 10]]);
+ *
+ * var cleaned = turf.cleanCoords(line).geometry.coordinates;
+ * //= [[0, 0], [0, 10]]
+ */
+module.exports = function (geojson, mutate) {
+    if (!geojson) throw new Error('geojson is required');
+    var type = getGeomType(geojson);
+    var coords = getCoords(geojson);
+
+    // Store new "clean" points in this Array
+    var newCoords = [];
+
+    switch (type) {
+    case 'LineString':
+        newCoords = cleanCoords(geojson, mutate);
+        break;
+    case 'MultiLineString':
+    case 'Polygon':
+        for (var i = 0; i < coords.length; i++) {
+            var line = coords[i];
+            newCoords.push(cleanCoords(line));
+        }
+        break;
+    case 'MultiPolygon':
+        for (var j = 0; j < coords.length; j++) {
+            var polys = coords[j];
+            var polyPoints = [];
+            for (var p = 0; p < polys.length; p++) {
+                var ring = polys[p];
+                polyPoints.push(cleanCoords(ring));
+            }
+            newCoords.push(polyPoints);
+        }
+        break;
+    case 'Point':
+        return geojson;
+    case 'MultiPoint':
+        var existing = {};
+        for (var i = 0; i < coords.length; i++) {
+            var point = coords[i];
+            var key = point.join('-');
+            if (!existing.hasOwnProperty(key)) {
+                newCoords.push(point);
+                existing[key] = true
+            }
+        }
+        break;
+    default:
+        throw new Error(type + ' geometry not supported');
+    }
+
+    if (mutate !== true) geojson = clone(geojson, false);
+
+    if (geojson.coordinates) geojson.coordinates = newCoords;
+    else geojson.geometry.coordinates = newCoords;
+    return geojson;
+};
+
+function cleanCoords(line) {
+    var points = getCoords(line);
+
+    var prevPoint, point, nextPoint;
+    var newPoints = [];
+    var secondToLast = points.length - 1;
+
+    newPoints.push(points[0]);
+    for (var i = 1; i < secondToLast; i++) {
+        prevPoint = points[i - 1];
+        point = points[i];
+        nextPoint = points[i + 1];
+
+        if (!isPointOnLineSegment(prevPoint, nextPoint, point)) {
+            newPoints.push(point);
+        }
+    }
+    newPoints.push(nextPoint);
+    return newPoints;
+}
+
+/**
+ * Returns if `point` is on the segment between `start` and `end`.
+ * Borrowed from `@turf/boolean-point-on-line` to speed up the evaluation
+ *
+ * @private
+ * @param {Array<number>} start coord pair of start of line
+ * @param {Array<number>} end coord pair of end of line
+ * @param {Array<number>} point coord pair of point to check
+ * @returns {boolean} true/false
+ */
+function isPointOnLineSegment(start, end, point) {
+    var x = point[0], y = point[1];
+    var startX = start[0], startY = start[1];
+    var endX = end[0], endY = end[1];
+
+    var dxc = x - startX;
+    var dyc = y - startY;
+    var dxl = endX - startX;
+    var dyl = endY - startY;
+    var cross = dxc * dyl - dyc * dxl;
+
+    if (cross !== 0) return false;
+    else if (Math.abs(dxl) >= Math.abs(dyl)) return dxl > 0 ? startX <= x && x <= endX : endX <= x && x <= startX;
+    else return dyl > 0 ? startY <= y && y <= endY : endY <= y && y <= startY;
+}

packages/turf-clean-coords/package.json

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+{
+  "name": "@turf/clean-coords",
+  "version": "4.5.0",
+  "description": "turf clean-coords module",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "files": [
+    "index.js",
+    "index.d.ts"
+  ],
+  "scripts": {
+    "test": "node test.js",
+    "bench": "node bench.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/Turfjs/turf.git"
+  },
+  "keywords": [
+    "turf",
+    "gis",
+    "clean-coords"
+  ],
+  "author": "Turf Authors",
+  "contributors": [
+    "Stefano Borghi <@stebogit>"
+  ],
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/Turfjs/turf/issues"
+  },
+  "homepage": "https://github.com/Turfjs/turf",
+  "devDependencies": {
+    "@turf/helpers": "4.5.2",
+    "benchmark": "^2.1.4",
+    "write-json-file": "^2.2.0",
+    "load-json-file": "^2.0.0",
+    "tape": "^4.6.3"
+  },
+  "dependencies": {
+    "@turf/clone": "4.5.2",
+    "@turf/invariant": "4.5.2"
+  }
+}

packages/turf-clean-coords/test.js

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+const fs = require('fs');
+const test = require('tape');
+const path = require('path');
+const load = require('load-json-file');
+const {multiPoint, lineString, multiPolygon} = require('@turf/helpers');
+const write = require('write-json-file');
+const cleanCoords = require('./');
+
+const directories = {
+    in: path.join(__dirname, 'test', 'in') + path.sep,
+    out: path.join(__dirname, 'test', 'out') + path.sep
+};
+
+const fixtures = fs.readdirSync(directories.in).map(filename => {
+    return {
+        filename,
+        name: path.parse(filename).name,
+        geojson: load.sync(directories.in + filename)
+    };
+});
+
+test('turf-clean-coords', t => {
+    for (const {filename, name, geojson}  of fixtures) {
+        const results = cleanCoords(geojson);
+
+        if (process.env.REGEN) write.sync(directories.out + filename, results);
+        t.deepEqual(results, load.sync(directories.out + filename), name);
+    }
+    t.end();
+});
+
+test('turf-clean-coords -- extras', t => {
+    t.equal(cleanCoords(multiPoint([[0, 0], [0, 0], [2, 2]])).geometry.coordinates.length, 2);
+    t.end();
+});
+
+test('turf-clean-coords -- throws', t => {
+    t.throws(() => cleanCoords(null), /geojson is required/, 'missing geojson');
+    t.end();
+});
+
+test('turf-clean-coords -- prevent input mutation', t => {
+    const line = lineString([[0, 0], [1, 1], [2, 2]], {foo: 'bar'});
+    cleanCoords(line);
+    const lineBefore = JSON.parse(JSON.stringify(line));
+    t.deepEqual(lineBefore, line, 'line should NOT be mutated');
+
+    const multiPoly = multiPolygon([
+        [[[0, 0], [1, 1], [2, 2], [2, 0], [0, 0]]],
+        [[[0, 0], [0, 5], [5, 5], [5, 5], [5, 0], [0, 0]]]
+    ], {hello: 'world'});
+    const multiPolyBefore = JSON.parse(JSON.stringify(multiPoly));
+    cleanCoords(multiPoly);
+    t.deepEqual(multiPolyBefore, multiPoly, 'multiPolygon should NOT be mutated');
+
+    const cleanLine = cleanCoords(line, true);
+    t.deepEqual(cleanLine, line, 'line should be mutated');
+    t.end();
+});