Other frequently-used names for key reversal include "one-day reversal" and "reversal day."
How Does a Key Reversal Work?
Depending on which way the stock is trending, a key reversal day occurs when:
In an uptrend -- prices hit a new high and then close near the previous day's lows.
In a downtrend -- prices hit a new low, but close near the previous day's highs
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.