Issue #107

src/Selection.js

@@ -11,6 +11,7 @@ export default class Selection {
 
   constructor(target, body) {
     this.underlying = {
+      '@context': 'http://www.w3.org/ns/anno.jsonld',
       type: 'Selection',
       body: body || [],
       target
@@ -29,6 +30,10 @@ export default class Selection {
     return cloned;
   }
 
+  get context() {
+    return this.underlying['@context'];
+  }
+
   get type() {
     return this.underlying.type;
   }
@@ -87,7 +92,6 @@ export default class Selection {
 
   toAnnotation = () => {
     const a = Object.assign({}, this.underlying, {
-      '@context': 'http://www.w3.org/ns/anno.jsonld',
       'type': 'Annotation',
       'id': `#${uuid()}`
     });

src/WebAnnotation.js

@@ -51,6 +51,10 @@ export default class WebAnnotation {
     return this.underlying.id;
   }
 
+  get context() {
+    return this.underlying['@context'];
+  }
+
   get type() {
     return this.underlying.type;
   }

src/editor/Editor.jsx

@@ -260,6 +260,20 @@ export default class Editor extends Component {
     }
   }
 
+  /**
+   * Adds a URI to the context field
+   */
+  onAddContext = uri => {
+    const { currentAnnotation } = this.state;
+    const context = Array.isArray(currentAnnotation.context) ?
+      currentAnnotation.context :  [ currentAnnotation.context ];
+
+    if (context.indexOf(uri) < 0) {
+      context.push(uri);
+      this.updateCurrentAnnotation({ '@context': context });
+    }
+  }
+
   onCancel = () =>
     this.props.onCancel(this.props.annotation);
 
@@ -335,6 +349,7 @@ export default class Editor extends Component {
                 onUpsertBody: this.onUpsertBody,
                 onBatchModify: this.onBatchModify,
                 onSetProperty: this.onSetProperty,
+                onAddContext: this.onAddContext,
                 onSaveAndClose: this.onOk
               })
             )}

src/editor/widgets/WrappedWidget.jsx

@@ -19,6 +19,7 @@ export default class WrappedWidget extends Component {
       onRemoveBody: (body, saveImmediately) => props.onRemoveBody(body, saveImmediately),
       onBatchModify: (diffs, saveImmediately)  => props.onBatchModify(diffs, saveImmediately),
       onSetProperty: (property, value) =>  props.onSetProperty(property, value),
+      onAddContext: uri => props.onAddContext(uri),
       onSaveAndClose: () => props.onSaveAndClose()
     });