Added FaceMatcher.toJSON() & FaceMatcher.fromJSON(), with unit tests

src/globalApi/FaceMatcher.ts

@@ -67,4 +67,19 @@ export class FaceMatcher {
       : new FaceMatch('unknown', bestMatch.distance)
   }
 
+  public static toJSON(matcher: FaceMatcher, pretty = false): string {
+    return JSON.stringify(matcher, null, pretty ? 2 : undefined);
+  }
+
+  public static fromJSON(jsonString: string): FaceMatcher {
+    const poco: any = JSON.parse(jsonString);
+    const labeledDescriptors = poco._labeledDescriptors
+      .map(({ _label, _descriptors }: { _label: string, _descriptors: any }) => {
+        return new LabeledFaceDescriptors(_label, _descriptors.map((d: any) => {
+          return new Float32Array(Object.values(d));
+        }));
+      });
+    return new FaceMatcher(labeledDescriptors, poco._distanceThreshold);
+  }
+
 }
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test/tests/globalApi/FaceMatcher.test.ts

+import { FaceMatcher } from '../../../src/globalApi/FaceMatcher';
+import { LabeledFaceDescriptors } from '../../../src';
+
+describe('globalApi', () => {
+
+  describe('FaceMatcher', () => {
+
+    const json = '{"_distanceThreshold":123.321,"_labeledDescriptors":[{"_label":"foo","_descriptors":[{"0":1,"1":2,"2":3},{"0":4,"1":5,"2":6}]},{"_label":"bar","_descriptors":[{"0":7,"1":8,"2":9},{"0":3,"1":2,"2":1}]}]}';
+    const dt = 123.321;
+    const l1 = 'foo';
+    const l2 = 'bar';
+    const f1 = new Float32Array([1, 2, 3]);
+    const f2 = new Float32Array([4, 5, 6]);
+    const f3 = new Float32Array([7, 8, 9]);
+    const f4 = new Float32Array([3, 2, 1]);
+    const lds = [
+      new LabeledFaceDescriptors(l1, [f1, f2]),
+      new LabeledFaceDescriptors(l2, [f3, f4])
+    ];
+
+    it('toJSON()', () => {
+      const fm = new FaceMatcher(lds, dt);
+
+      expect(FaceMatcher.toJSON(fm)).toBe(json);
+    });
+
+    it('fromJSON()', () => {
+      const fm = FaceMatcher.fromJSON(json);
+
+      expect(fm.distanceThreshold).toBe(dt);
+      expect(fm.labeledDescriptors.length).toBe(2);
+      expect(fm.labeledDescriptors[0].label).toBe(l1);
+      expect(fm.labeledDescriptors[0].descriptors.length).toBe(2);
+      expect(fm.labeledDescriptors[0].descriptors[0]).toEqual(f1);
+      expect(fm.labeledDescriptors[0].descriptors[1]).toEqual(f2);
+      expect(fm.labeledDescriptors[1].label).toBe(l2);
+      expect(fm.labeledDescriptors[1].descriptors.length).toBe(2);
+      expect(fm.labeledDescriptors[1].descriptors[0]).toEqual(f3);
+      expect(fm.labeledDescriptors[1].descriptors[1]).toEqual(f4);
+    });
+
+    it('toJSON() => fromJSON()', () => {
+      const fm = FaceMatcher.fromJSON(FaceMatcher.toJSON(new FaceMatcher(lds, dt)));
+
+      expect(fm.distanceThreshold).toBe(dt);
+      expect(fm.labeledDescriptors.length).toBe(2);
+      expect(fm.labeledDescriptors[0].label).toBe(l1);
+      expect(fm.labeledDescriptors[0].descriptors.length).toBe(2);
+      expect(fm.labeledDescriptors[0].descriptors[0]).toEqual(f1);
+      expect(fm.labeledDescriptors[0].descriptors[1]).toEqual(f2);
+      expect(fm.labeledDescriptors[1].label).toBe(l2);
+      expect(fm.labeledDescriptors[1].descriptors.length).toBe(2);
+      expect(fm.labeledDescriptors[1].descriptors[0]).toEqual(f3);
+      expect(fm.labeledDescriptors[1].descriptors[1]).toEqual(f4);
+    });
+
+  });
+
+});
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