Basic implementation

Author: jake-low

.gitignore

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+node_modules/
+dist/

LICENSE

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+ISC License
+
+Copyright 2024 OpenStreetMap US
+
+Permission to use, copy, modify, and/or distribute this software for any purpose
+with or without fee is hereby granted, provided that the above copyright notice
+and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+THIS SOFTWARE.

README.md

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+# osm-changeset-xml-parser
+
+Parse OpenStreetMap Changeset metadata XML documents into plain JavaScript objects.
+
+**Note: you may not need this package.** The OSM API is capable of returning this metadata in JSON natively if you append `.json` to the endpoint URL, like this:
+
+```
+curl -i 'https://api.openstreetmap.org/api/0.6/changeset/133061984.json'
+```
+
+## Installation
+
+```
+npm install @osmcha/osm-changeset-xml-parser
+```
+
+## Usage
+
+```js
+import parseChangesetXML from "@osmcha/osm-changeset-xml-parser";
+let changeset = await parseChangesetXML(xmlString);
+```
+
+## Example input & output
+
+Input:
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<osm version="0.6" generator="openstreetmap-cgimap 2.0.1 (1849 spike-07.openstreetmap.org)" copyright="OpenStreetMap and contributors" attribution="http://www.openstreetmap.org/copyright" license="http://opendatacommons.org/licenses/odbl/1-0/">
+ <changeset id="155530622" created_at="2024-08-20T21:36:16Z" closed_at="2024-08-20T21:36:17Z" open="false" user="jake-low" uid="8794039" min_lat="47.6647943" min_lon="-121.2881568" max_lat="47.6647943" max_lon="-121.2881568" comments_count="0" changes_count="1">
+  <tag k="changesets_count" v="1992"/>
+  <tag k="comment" v="Skykomish, WA: add name, operator, and website to Necklace Valley Trailhead"/>
+  <tag k="created_by" v="iD 2.29.0"/>
+  <tag k="host" v="https://www.openstreetmap.org/edit"/>
+  <tag k="imagery_used" v="Bing Maps Aerial"/>
+  <tag k="locale" v="en-US"/>
+ </changeset>
+</osm>
+```
+
+Output:
+
+```json
+{
+  "version": "0.6",
+  "generator": "openstreetmap-cgimap 2.0.1 (1849 spike-07.openstreetmap.org)",
+  "copyright": "OpenStreetMap and contributors",
+  "attribution": "http://www.openstreetmap.org/copyright",
+  "license": "http://opendatacommons.org/licenses/odbl/1-0/",
+  "changeset": {
+    "id": 155530622,
+    "created_at": "2024-08-20T21:36:16Z",
+    "closed_at": "2024-08-20T21:36:17Z",
+    "open": false,
+    "user": "jake-low",
+    "uid": 8794039,
+    "min_lat": 47.6647943,
+    "min_lon": -121.2881568,
+    "max_lat": 47.6647943,
+    "max_lon": -121.2881568,
+    "comments_count": 0,
+    "changes_count": 1,
+    "tags": {
+      "changesets_count": "1992",
+      "comment": "Skykomish, WA: add name, operator, and website to Necklace Valley Trailhead",
+      "created_by": "iD 2.29.0",
+      "host": "https://www.openstreetmap.org/edit",
+      "imagery_used": "Bing Maps Aerial",
+      "locale": "en-US"
+    }
+  }
+}
+```

index.js

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+import sax from "sax";
+
+const TYPED_ATTRS = [
+  "id",
+  "uid",
+  "min_lon",
+  "min_lat",
+  "max_lon",
+  "max_lat",
+  "comments_count",
+  "changes_count",
+  "open",
+];
+
+/*
+ * Parse OSM Changeset Metadata XML, of the form returned by
+ * https://www.openstreetmap.org/api/0.6/changeset/:id
+ * (Contains changeset's bbox, timestamp, comment, and authorship)
+ */
+function parseChangesetXML(xmlString) {
+  return new Promise((resolve, reject) => {
+    let parser = sax.parser(true /* strict mode */, { lowercase: true });
+    let result = {};
+
+    parser.onopentag = (node) => {
+      let name = node.name, attrs = node.attributes;
+      switch (name) {
+        case "osm":
+          Object.assign(result, attrs);
+          break;
+        case "changeset":
+          Object.assign((result.changeset ||= {}), attrs);
+          break;
+        case "tag":
+          Object.assign((result.changeset.tags ||= {}), { [attrs.k]: attrs.v });
+          break;
+      }
+    };
+
+    parser.onend = () => {
+      let { changeset } = result;
+      for (let attr of TYPED_ATTRS) {
+        changeset[attr] = JSON.parse(changeset[attr]);
+      }
+      resolve(result);
+    };
+
+    parser.onerror = reject;
+
+    parser.write(xmlString);
+    parser.close();
+  });
+}
+
+export default parseChangesetXML;