fixed linting

services/spelling/app/js/ASpellWorker.js

@@ -90,7 +90,10 @@ class ASpellWorker {
         )
         this.callback = null
       } else {
-        logger.warn({ error: err, ...errInfo }, 'aspell worker error')
+        logger.warn(
+          Object.assign({ error: err }, errInfo),
+          'aspell worker error'
+        )
       }
     })
     this.pipe.stdin.on('error', err => {
@@ -119,10 +122,7 @@ class ASpellWorker {
         this.callback = null
       } else {
         logger.warn(
-          {
-            error: err,
-            ...errInfo
-          },
+          Object.assign({ error: err }, errInfo),
           'aspell worker error on stdin'
         )
       }
@@ -134,7 +134,7 @@ class ASpellWorker {
     this.pipe.stdout.on('data', data => {
       // We receive the language code from Aspell as the end of data marker in
       // the data.  The input is a utf8 encoded string.
-      let oldPos = output.length
+      const oldPos = output.length
       output = output + data
       // The end marker may cross the end of a chunk, so we optimise the search
       // using the regex lastIndex property.