OPEN-SOURCE SCRIPT
Unmitigated Gaps by Midniteblade
4H Unmitigated Gaps — Build Summary
A Pine Script indicator that finds and draws unmitigated Fair Value Gaps (FVGs) on the 4H timeframe, from any chart timeframe you're viewing.
What it does
An FVG is a three-candle imbalance — a move so fast that price left a gap no two-way auction filled. The script looks for two kinds:
Bullish FVG — candle 3's low is above candle 1's high (l3 > h1). Price skipped up; the gap sits below.
Bearish FVG — candle 3's high is below candle 1's low (h3 < l1). Price skipped down; the gap sits above.
Each gap is drawn as a box and stays on the chart until price trades back through it ("mitigated"). The info table reports live counts, the nearest gap above/below price, and the stored 4H period data.
The three bugs we hit — and why each mattered
1. max_bars_back rejected built-in series. The script needed deep history for dynamic indexing. Pine refused max_bars_back(volume, 5000) because volume, close, open, hlc3 are built-ins — the parameter needs a user-declared series. Fix: assign each to a variable first, then declare.
2. The history buffer was keyed to the wrong variable. This is the subtle one. We declared history on the new variables — but the loop still indexed volume[...], close[...] directly. Pine sizes its buffer for the exact series you reference, so the declarations did nothing and the runtime error came back. Fix: swap every dynamic index in the loop to the declared variables.
Lesson: declaring max_bars_back on a variable only helps if that variable is what you actually index. The declaration follows the reference, not the value.
3. The live test compared a bar against itself. The ongoing check read candle 3 from the n-1 slot while also treating the live bar as a separate candle — but those were the same bar. It could never detect a new gap. Fix: compare the newest stored period against the two before it, so all three candles are genuinely distinct.
Lesson: when a test returns zero forever, check whether its inputs are actually independent before assuming the market is quiet. A debug row showing the raw stored values is what exposed this.
Debug technique worth stealing
We added a table row printing the last three stored htfH/htfL pairs — [n-3 | n-2 | n-1]. That single row let us verify the array was storing sane values and cross-check them against the table's own "Cur/Prev period" rows. When the numbers matched, the storage was proven correct; when the live test still failed, the bug had to be in the comparison logic.
Print your raw inputs, not just your outputs. An output of 0 tells you nothing. The inputs tell you why.
Takeaway
Three separate bugs, each hidden behind the last. The first fix looked like it worked until the second surfaced; the second looked complete until the third appeared. Debugging in sequence — fix, re-run, read the new error — is what got there. Skipping verification after a fix would have left all three in place.
A Pine Script indicator that finds and draws unmitigated Fair Value Gaps (FVGs) on the 4H timeframe, from any chart timeframe you're viewing.
What it does
An FVG is a three-candle imbalance — a move so fast that price left a gap no two-way auction filled. The script looks for two kinds:
Bullish FVG — candle 3's low is above candle 1's high (l3 > h1). Price skipped up; the gap sits below.
Bearish FVG — candle 3's high is below candle 1's low (h3 < l1). Price skipped down; the gap sits above.
Each gap is drawn as a box and stays on the chart until price trades back through it ("mitigated"). The info table reports live counts, the nearest gap above/below price, and the stored 4H period data.
The three bugs we hit — and why each mattered
1. max_bars_back rejected built-in series. The script needed deep history for dynamic indexing. Pine refused max_bars_back(volume, 5000) because volume, close, open, hlc3 are built-ins — the parameter needs a user-declared series. Fix: assign each to a variable first, then declare.
2. The history buffer was keyed to the wrong variable. This is the subtle one. We declared history on the new variables — but the loop still indexed volume[...], close[...] directly. Pine sizes its buffer for the exact series you reference, so the declarations did nothing and the runtime error came back. Fix: swap every dynamic index in the loop to the declared variables.
Lesson: declaring max_bars_back on a variable only helps if that variable is what you actually index. The declaration follows the reference, not the value.
3. The live test compared a bar against itself. The ongoing check read candle 3 from the n-1 slot while also treating the live bar as a separate candle — but those were the same bar. It could never detect a new gap. Fix: compare the newest stored period against the two before it, so all three candles are genuinely distinct.
Lesson: when a test returns zero forever, check whether its inputs are actually independent before assuming the market is quiet. A debug row showing the raw stored values is what exposed this.
Debug technique worth stealing
We added a table row printing the last three stored htfH/htfL pairs — [n-3 | n-2 | n-1]. That single row let us verify the array was storing sane values and cross-check them against the table's own "Cur/Prev period" rows. When the numbers matched, the storage was proven correct; when the live test still failed, the bug had to be in the comparison logic.
Print your raw inputs, not just your outputs. An output of 0 tells you nothing. The inputs tell you why.
Takeaway
Three separate bugs, each hidden behind the last. The first fix looked like it worked until the second surfaced; the second looked complete until the third appeared. Debugging in sequence — fix, re-run, read the new error — is what got there. Skipping verification after a fix would have left all three in place.
Skrip open-source
Dengan semangat TradingView yang sesungguhnya, pembuat skrip ini telah menjadikannya sebagai sumber terbuka, sehingga para trader dapat meninjau dan memverifikasi fungsinya. Salut untuk penulisnya! Meskipun Anda dapat menggunakannya secara gratis, perlu diingat bahwa penerbitan ulang kode ini tunduk pada Tata Tertib kami.
Pernyataan Penyangkalan
Informasi dan publikasi ini tidak dimaksudkan, dan bukan merupakan, saran atau rekomendasi keuangan, investasi, trading, atau jenis lainnya yang diberikan atau didukung oleh TradingView. Baca selengkapnya di Ketentuan Penggunaan.
Skrip open-source
Dengan semangat TradingView yang sesungguhnya, pembuat skrip ini telah menjadikannya sebagai sumber terbuka, sehingga para trader dapat meninjau dan memverifikasi fungsinya. Salut untuk penulisnya! Meskipun Anda dapat menggunakannya secara gratis, perlu diingat bahwa penerbitan ulang kode ini tunduk pada Tata Tertib kami.
Pernyataan Penyangkalan
Informasi dan publikasi ini tidak dimaksudkan, dan bukan merupakan, saran atau rekomendasi keuangan, investasi, trading, atau jenis lainnya yang diberikan atau didukung oleh TradingView. Baca selengkapnya di Ketentuan Penggunaan.