Tradingview pine ; change v2 to v3 : Undeclared identifier Error

Question

I try to modify pine version 2 to version 3.

But this error happens.

trendState = closeSeries > openSeries ? true : closeSeries < openSeries ? false : trendState[1]

Undeclared identifier trendState

I appreciate your help.

BR

Sho

Answer 1

Starting in v3, variables need to be initialized before you can refer to them in a re-assignment:

trendState = false
trendState := closeSeries > openSeries ? true : closeSeries < openSeries ? false : trendState[1]