# Threshold what-if

> What a new alert threshold would have done. Sample data: hourly success rate, Oct 10 to today, 14 alerts at 96%, 3 at a proposed 95%.

- Type 111 · Change over time
- Component: `<ThresholdWhatIf>`, the same name as the Figma component
- Install: `npx shadcn add @chartory/threshold-what-if` (Code and Complete plans)
- Type page: https://usechartory.com/charts/threshold-what-if

## Installation

1. **Set up the registry once.** Your token in .env and @chartory in components.json. Skip this when another chart is already installed. [Installation guide](https://usechartory.com/docs/installation)

2. **Add the chart.** One command adds the Threshold what-if component to your project.

```bash
npx shadcn add @chartory/threshold-what-if
```

3. **Use it.** Pass your rows. The props are the Figma properties.

usage.tsx:

```tsx
import { ThresholdWhatIf }
  from "@/components/chartory/threshold-what-if"

<ThresholdWhatIf
  data={hourlySuccess}
  size="m"
  legend
/>
```

## Props

### `<ThresholdWhatIf>`

Every prop but data is a Figma property with the same name and values.

| Prop | Type | Default | Note |
| --- | --- | --- | --- |
| data | ThresholdWhatIfData | Required | The chart's data. The tables below list every field. |
| size | "xs" \| "s" \| "m" \| "l" | "m" | The size class. Each one is laid out again from the data. |
| legend | boolean | true | Shows the legend row under the plot. |

### ThresholdWhatIfData

The data prop: one object for the whole chart.

| Prop | Type | Default | Note |
| --- | --- | --- | --- |
| vals | number[] | Required | The values, in order. |
| min | number | Required | The bottom of the value scale. |
| max | number | Required | The top of the value scale. |
| now | ThresholdWhatIfNow | Required | Now: where it is and its label. |
| prop | ThresholdWhatIfProp | Required | The proposed value and its label. |
| ticks | [number, string][] | Required | The axis ticks: [value, label] pairs. |
| xl | [number, string][] | Required | The x axis labels: [position, label] pairs. |

### ThresholdWhatIfNow

The now object.

| Prop | Type | Default | Note |
| --- | --- | --- | --- |
| v | number | Required | The value. |
| text | string | Required | The label as shown. |
| lane | string | Required | The lane it sits in. |

### ThresholdWhatIfProp

The prop object.

| Prop | Type | Default | Note |
| --- | --- | --- | --- |
| v | number | Required | The value. |
| text | string | Required | The label as shown. |
| lane | string | Required | The lane it sits in. |

## Threshold what-if chart: a React and Figma chart in four sizes

### What does a threshold what-if chart show?

A threshold what-if chart replays a measure against the current alert threshold and a proposed one, and counts the alerts each would have fired. You see the trade-off before you change the rule. Use it for alert tuning and SLO reviews.

Chartory ships it as a Figma component and a React component with the same name. The code installs from the shadcn registry with one command and lands in your project as a file you own.

### What is the Threshold what-if component?

It is one **<ThresholdWhatIf>** component. Its props are the Figma properties with the same names and values, and the props table above lists them. The data is a measure over time, two thresholds.

Sizes **XS**, **S**, **M** and **L** re-lay the chart out from the data instead of scaling it, so labels stay readable at every size.

### When should I use it?

- **Are two thresholds compared?** Yes means the threshold what-if fits.
- **Is the alert count the point?** Yes means the threshold what-if fits.
- **Is it over time?** Yes means the threshold what-if fits.

### When does another type fit better?

- **One target to hold.** Use Target trend instead.
- **The full range of thresholds.** Use Threshold sweep instead.
- **One value per item.** Use Horizontal bars instead.

## Threshold what-if questions

### Does the Threshold what-if chart work with shadcn/ui?

Yes. It installs through the shadcn registry with the shadcn CLI, and the file lands in your project.

### How do I install it?

Add your token and the @chartory registry once, then run npx shadcn add @chartory/threshold-what-if. The Installation guide has the steps.

### Can my coding agent install it?

Yes. Connect the Chartory MCP server and ask for the threshold what-if chart; the agent runs the same command and you review the diff.

### What data does it expect?

A measure over time, two thresholds. The sample data comes with the component, and the props table lists every field.

### Which sizes does it ship in?

XS, S, M and L, in Figma and in code. Each size is laid out again from the data, so text and lines keep their size.

### Is it in the Figma file too?

Yes. chart/111-threshold-what-if has the same properties as the component.

### Does it follow light and dark mode?

Yes. Every paint is a token, so the chart follows light and dark mode and the collection you pick.

### Which plan has the code?

Code and Complete. Figma has the Figma file only.