Functions Log: add better handling for unknown values (#1377)

* add better handling for unknown values

fixes #1343

* entry for fixing functions:log

Author: bkendall

changelog.txt

@@ -1 +1,2 @@
 * Set FIRESTORE_EMULATOR_HOST env var in "emulators:exec".
+* Fixes bug in printing Function logs when the text payload was undefined.

src/commands/functions-log.ts

@@ -46,9 +46,9 @@ module.exports = new Command("functions:log")
         const entry = entries[i];
         logger.info(
           entry.timestamp,
-          entry.severity.substring(0, 1),
-          entry.resource.labels.function_name + ":",
-          entry.textPayload
+          _.get(entry, "severity", "?").substring(0, 1),
+          _.get(entry, "resource.labels.function_name") + ":",
+          _.get(entry, "textPayload", "")
         );
       }
       if (_.isEmpty(entries)) {