resolve eslint errors that came through commit 22c0840dc7719f36ea8f0b9e1e56b57e1d7d

[ashuvssut]

commit 22c0840dc7719f36ea8f0b9e1e56b57e1d7d converted all tab to spaces because of bad config prettier extension. That bad config doesnt follow eslint rules

for that, issue #1019 should be resolved

then, these eslint errors need to be resolved