added logic of metadata.json

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@watergis/mbtiles2pbf",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "This module will extract pbf files from mbtile by using mbutil.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

src/mbtiles2pbf.ts

@@ -48,6 +48,7 @@ class mbtiles2pbf {
           const count = db.prepare('SELECT count(*) FROM tiles').get()[
             'count(*)'
           ];
+
           let c = 0;
           for (const r of db.prepare('SELECT * FROM tiles').iterate()) {
             const buf = zlib.unzipSync(r.tile_data);
@@ -58,6 +59,19 @@ class mbtiles2pbf {
             fs.writeFileSync(`${this.dist}/${z}/${x}/${y}${this.ext}`, buf);
             this.report(++c, count, `${this.dist}/${z}/${x}/${y}${this.ext}`);
           }
+
+          let metadata: { [key: string]: string } = {};
+          var rows: Array<{ [key: string]: string }> = db
+            .prepare('SELECT name, value FROM metadata')
+            .all();
+          rows.forEach((row: { [key: string]: string }) => {
+            metadata[row.name] = row.value;
+          });
+          fs.writeFileSync(
+            `${this.dist}/metadata.json`,
+            JSON.stringify(metadata, null, 4)
+          );
+
           db.close();
           resolve(c);
         } catch (err) {

test/index.test.ts

@@ -2,6 +2,7 @@
 
 import { Mbtiles2Pbf, FileExtension } from '../src/index';
 import rimraf from 'rimraf';
+import fs from 'fs-extra';
 
 const src = __dirname + '/test.mbtiles';
 const dist = __dirname + '/tiles';
@@ -11,12 +12,14 @@ describe('extract vector tiles', (): void => {
     const mbtile2pbf = new Mbtiles2Pbf(src, dist, FileExtension.PBF);
     const res = await mbtile2pbf.run();
     expect(res).toBe(36);
+    expect(fs.existsSync(dist+'/metadata.json')).toBeTruthy();
     rimraf.sync(dist);
   });
   test('extract to mvt', async () => {
     const mbtile2pbf = new Mbtiles2Pbf(src, dist, FileExtension.MVT);
     const res = await mbtile2pbf.run();
     expect(res).toBe(36);
+    expect(fs.existsSync(dist+'/metadata.json')).toBeTruthy();
     rimraf.sync(dist);
   });
 });