service2.js: Fix empty paragraph handling

service2.js

@@ -432,9 +432,9 @@ class BesDOMService extends BesTreeService {
       case Node.ELEMENT_NODE:
         if (this.isBlockElement(node)) {
           // Block elements are grammar-checked independently.
-          this.onProofing()
           let result = this.getProofing(node)
           if (result) {
+            this.onProofing()
             this.onProofingProgress(result.matches.length)
             return [{ text: `<${node.tagName}/>`, node: node, markup: true }]
           }
@@ -444,6 +444,7 @@ class BesDOMService extends BesTreeService {
             data = data.concat(this.proofNode(el2, abortController))
           if (data.some(x => !x.markup && !/^\s*$/.test(x.text))) {
             // Block element contains some text.
+            this.onProofing()
             const signal = abortController.signal
             fetch(
               new Request(besUrl + '/check', {
@@ -948,12 +949,16 @@ class BesPlainTextService extends BesService {
       paragraphRange.setEnd(nodes[nodeIdx].node, end - nodes[nodeIdx].start)
       while (nodeIdx < nodes.length && nodes[nodeIdx].end <= end) nodeIdx++
 
-      this.onProofing()
       let result = this.getProofing(paragraphRange)
       if (result) {
+        this.onProofing()
         this.onProofingProgress(result.matches.length)
         continue
       }
+      let paragraphText = text.substring(start, end)
+      if (!/^\s*$/.test(paragraphText)) {
+        // Paragraph contains some text.
+        this.onProofing()
         const signal = this.abortController.signal
         fetch(
           new Request(besUrl + '/check', {
@@ -966,7 +971,7 @@ class BesPlainTextService extends BesService {
               data: JSON.stringify({
                 annotation: [
                   {
-                  text: text.substring(start, end)
+                    text: paragraphText
                   }
                 ]
               }),
@@ -1016,6 +1021,7 @@ class BesPlainTextService extends BesService {
           })
           .catch(error => this.onFailedProofingResult(error))
       }
+    }
 
     this.onProofingProgress(0)
   }