Fix race condition on setting request body and headers

packages/insomnia-app/app/ui/components/editors/body/body-editor.js

@@ -80,37 +80,37 @@ class BodyEditor extends React.PureComponent<Props> {
     const { onChange, onChangeHeaders, request } = this.props;
     const headers = clone(request.headers);
 
-    let contentTypeHeader = getContentTypeHeader(headers);
-
-    if (!contentTypeHeader) {
-      contentTypeHeader = { name: 'Content-Type', value: CONTENT_TYPE_FILE };
-      headers.push(contentTypeHeader);
-    }
-
-    // Update Content-Type header if the user wants
-    const contentType = contentTypeHeader.value;
-    const newContentType = mimes.lookup(path) || CONTENT_TYPE_FILE;
-    if (contentType !== newContentType) {
-      contentTypeHeader.value = newContentType;
-      showModal(AskModal, {
-        title: 'Change Content-Type',
-        message: (
-          <p>
-            Do you want set the <span className="monospace">Content-Type</span> header to{' '}
-            <span className="monospace">{newContentType}</span>?
-          </p>
-        ),
-        onDone: saidYes => {
-          if (saidYes) {
-            onChangeHeaders(request, headers);
-          }
-        },
-      });
-    }
-
     const newBody = newBodyFile(path);
 
-    onChange(request, newBody);
+    onChange(request, newBody).then(request => {
+      let contentTypeHeader = getContentTypeHeader(headers);
+
+      if (!contentTypeHeader) {
+        contentTypeHeader = { name: 'Content-Type', value: CONTENT_TYPE_FILE };
+        headers.push(contentTypeHeader);
+      }
+
+      // Update Content-Type header if the user wants
+      const contentType = contentTypeHeader.value;
+      const newContentType = mimes.lookup(path) || CONTENT_TYPE_FILE;
+      if (contentType !== newContentType && path) {
+        contentTypeHeader.value = newContentType;
+        showModal(AskModal, {
+          title: 'Change Content-Type',
+          message: (
+            <p>
+              Do you want set the <span className="monospace">Content-Type</span> header to{' '}
+              <span className="monospace">{newContentType}</span>?
+            </p>
+          ),
+          onDone: saidYes => {
+            if (saidYes) {
+              onChangeHeaders(request, headers);
+            }
+          },
+        });
+      }
+    });
   }
 
   render() {