# Fractal Support and Resistance

`D08-F01-A11` · Geometric Chart Patterns → Pivots and Levels · archetype `record-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/geometric-chart-patterns/pivots-and-levels/fractal-support-and-resistance/
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 { fractalSupportAndResistance } from "fintech-algorithms/geometric-chart-patterns/pivots-and-levels/fractal-support-and-resistance";
```

## Signature

```ts
fractalSupportAndResistance(input)
```

Holds the most recent confirmed five-bar fractal high and low forward as resistance and support. This deliberately delegates to the same causal five-bar confirmation used by Fractal Chaos Bands, so a fractal at bar p is only reported from bar p+2 onward.

## 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 fractal window is fixed at five bars and no `parameters` key changes it, though `period` (default `20`, integer of at least 2) and `multiplier` (default `2`, at least `0`) are still validated when supplied. |

## Returns

`TopicResult`

`series` and `latest` carry `upper` and `lower`. The warm-up is at least four bars and then runs until the first fractal actually confirms, so `ready_at` is data-dependent (5 on the canonical fixture); once set, each level is held forward until the next fractal replaces it.

## Warm-up

The first `4 bars minimum, then until the first fractal confirms` positions are `null`. Indices 0 to 3 can never confirm a centred five-bar window. From index 4 the pivot under test is i-2, so `ready_at` is the first index at or after 4 whose centre bar is the extreme of its five-bar neighbourhood.

## Errors

- When `bars` is empty or is not an array — throws Error
- When `multiplier` is supplied as a negative number or is not finite — 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
fractalSupportAndResistance(input)
```

### Returns

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

```json
{
  "topic_id": "D08-F01-A11",
  "title": "Fractal Support and Resistance",
  "state": "calculated",
  "ready": true,
  "ready_at": 5,
  "series": {
    "upper": [null, null, null, null, null, 105.01857496],
    "lower": [null, null, null, null, null, null]
  },
  "latest": {
    "upper": 109.83623682,
    "lower": 101.07584902
  },
  "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/pivots-and-levels/fractal-support-and-resistance/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/geometric-chart-patterns/pivots-and-levels/fractal-support-and-resistance/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