# Four-Price Doji

`D06-F02-A11` · Price Action and Candlesticks → Single-Candle Patterns · archetype `record-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/price-action-and-candlesticks/single-candle-patterns/four-price-doji/
Agent skill: `npx skills add IslamBaraka90/Fintech-Algorithms-Library` — https://docs.thefintechbuilder.com/guides/agent-skill/

## Install and import

```bash
npm install fintech-algorithms
```

```ts
import { fourPriceDoji } from "fintech-algorithms/price-action-and-candlesticks/single-candle-patterns/four-price-doji";
```

## Signature

```ts
fourPriceDoji(input)
```

Marks each bar whose entire range and whose open-to-close distance both sit within a tick tolerance, the degenerate candle where all four prices are effectively the same.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is a chronologically ordered array of OHLCV rows; each needs a non-empty `timestamp` strictly greater than the previous row's and finite `open`, `high`, `low`, `close` and `volume`. The single-candle family validates `body_ratio` (default 0.05), `shadow_ratio` (default 0.35), `shadow_body_multiple` (default 2) and `tick_tolerance` (default 0.01) on every call, but this topic reads only `tick_tolerance`, the price distance at which a range and a body still count as zero. |

## Returns

`TopicResult`

`series.label` is `"neutral"` when both `high` minus `low` and the absolute open-to-close distance are within `tick_tolerance`, and `"none"` otherwise. `series.score` is `tick_tolerance` minus the larger of those two distances, so it is at or above zero exactly when the bar matches. `latest` carries the last value of each. There is no warm-up: unlike its siblings this topic has no positive-span guard, so both series hold a value for every bar and `ready_at` is 0.

## Warm-up

The first `0 bars` positions are `null`. Purely per-bar arithmetic with no smoothing state and no span guard, so neither `label` nor `score` is ever null and `ready_at` is 0.

## Errors

- When a bar has a non-finite price or volume, a negative volume, a `high` below its own open/low/close, a `low` above them, or a `timestamp` that does not advance — throws Error
- When `tick_tolerance` is not a finite number or is negative — throws Error
- When `input` is not an object, `input.parameters` is not an object, or `bars` is not an array holding at least one bar — throws Error

## Complexity

Time `O(n)`, space `O(n)`.

## Worked example

Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

### Input

`input`:

```json
{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}
```

### Call

```ts
fourPriceDoji(input)
```

### Returns

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

```json
{
  "topic_id": "D06-F02-A11",
  "title": "Four-Price Doji",
  "state": "calculated",
  "ready": true,
  "ready_at": 0,
  "series": {
    "label": ["none", "none", "none", "none", "none", "none"],
    "score": [
      -2.74500000000001,
      -3.3190167099999908,
      -3.748713730000011,
      -3.928635059999996,
      -3.819996080000001,
      -3.4596505999999945
    ]
  },
  "latest": {
    "label": "none",
    "score": -3.1108633100000045
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}
```

## Verification and provenance

Tier: **verified** (via E).

The worked example below is the figure published in this algorithm's article, replayed and asserted by the test suite on every build. The arithmetic cannot drift without the build failing.

Both tiers guarantee the signature. Full explanation: https://docs.thefintechbuilder.com/guides/verification/

Generated from the docs.json payload shipped inside fintech-algorithms@0.13.0.
The signature and parameter list are checked against the compiled implementation at build time,
so a description that contradicts the code fails the build rather than reaching this file.

## Links

- Article (how it works, step by step): https://thefintechbuilder.com/price-action-and-candlesticks/single-candle-patterns/four-price-doji/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/price-action-and-candlesticks/single-candle-patterns/four-price-doji/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/price-action-and-candlesticks/llms.txt