# Higher-High/Lower-Low Structure

`D08-F07-A16` · Geometric Chart Patterns → Market Structure, Breakouts, and Regimes · archetype `record-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/geometric-chart-patterns/market-structure-breakouts-and-regimes/higher-high-lower-low-structure/
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 { higherHighLowerLowStructure } from "fintech-algorithms/geometric-chart-patterns/market-structure-breakouts-and-regimes/higher-high-lower-low-structure";
```

## Signature

```ts
higherHighLowerLowStructure(input)
```

Reduces price to the higher-high / lower-low sequence traders read structure from, labelling each confirmed five-bar swing `HH`, `LH`, `HL` or `LL` against the previous swing of its kind. It shares a byte-identical state transition with the swing structure detector.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is the required OHLCV history, strictly ordered by `timestamp` and on a single adjustment basis. The five-bar swing window is fixed and no `parameters` key changes it; `period` (default `20`, integer of at least 2) is validated by the family but unused here. |

## Returns

`TopicResult`

`series` and `latest` carry `swing_high`, `swing_low` and the string series `structure`, whose values are `none`, `swing-high`, `swing-low`, `HH`, `LH`, `HL` or `LL`. The warm-up is four bars, so `ready_at` is 4.

## Warm-up

The first `4 bars` positions are `null`. A centred five-bar window is impossible before index 4. From there `structure` is never null; `swing_high` and `swing_low` remain null on every bar that does not confirm a swing.

## Errors

- When `bars` is empty or is not an array — throws Error
- When a bar's `high` or `low` is not a finite number — 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
higherHighLowerLowStructure(input)
```

### Returns

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

```json
{
  "topic_id": "D08-F07-A16",
  "title": "Higher-High/Lower-Low Structure",
  "state": "calculated",
  "ready": true,
  "ready_at": 4,
  "series": {
    "swing_high": [null, null, null, null, null, 105.01857496],
    "swing_low": [null, null, null, null, null, null],
    "structure": [null, null, null, null, "none", "swing-high"]
  },
  "latest": {
    "swing_high": null,
    "swing_low": null,
    "structure": "none"
  },
  "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/geometric-chart-patterns/market-structure-breakouts-and-regimes/higher-high-lower-low-structure/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/geometric-chart-patterns/market-structure-breakouts-and-regimes/higher-high-lower-low-structure/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/geometric-chart-patterns/llms.txt