fix(toJSON): handle array properties properly

src/Thing.ts

@@ -51,7 +51,9 @@ export default class Thing {
 
       let id = Reflect.getMetadata('property:id', this, key)
       let [context, term] = id.split(':')
-      if (value instanceof Thing) {
+      if (Array.isArray(value)) {
+        jsonld[term] = value.map(item => (item instanceof Thing) ? item.toJSONLD(false) : value)
+      } else if (value instanceof Thing) {
         jsonld[term] = value.toJSONLD(false)
       } else {
         jsonld[term] = value

tests/SoftwarePackage.test.ts

@@ -1,10 +1,29 @@
 import SoftwarePackage from '../src/SoftwarePackage'
 
-describe('SoftwarePackage', () => {
-  const node = new SoftwarePackage()
+test('type', () => {
+  const pkg = new SoftwarePackage()
+  expect(pkg.type).toEqual('SoftwarePackage')
+})
 
-  test('type', () => {
-    expect(node.type).toEqual('SoftwarePackage')
+test('toJSON', () => {
+  const pkg = new SoftwarePackage()
+  pkg.name = 'My package'
+  pkg.softwareRequirements = [
+    new SoftwarePackage({ name: 'another'}),
+    new SoftwarePackage({ name: 'yetAnother'})
+  ]
+  expect(pkg.toJSONLD()).toEqual({
+    "@context": "https://stencila.github.io/schema/context.jsonld",
+    "type": "SoftwarePackage",
+    "name": "My package",
+    "softwareRequirements": [
+      {
+        "type": "SoftwarePackage",
+        "name": "another"
+      }, {
+        "type": "SoftwarePackage",
+        "name": "yetAnother"
+      }
+    ]
   })
-
 })