# Node.js API

Use the Node API when you want to run React Doctor from another script or service.

```js
import { diagnose, summarizeDiagnostics, toJsonReport } from "react-doctor/api";

const result = await diagnose("./path/to/your/react-project");

console.log(result.score); // { score: 82, label: "Great" } or null
console.log(result.diagnostics); // Diagnostic[]
console.log(result.project); // detected framework, React version, etc.
```

## Diagnose options

`diagnose` accepts a second options object:

```js
const result = await diagnose("./path/to/your/react-project", {
  lint: true,
});
```

## Scan multiple projects

Pass `diagnose` an object with `projects` to scan several projects in one call. Use this for monorepos where each module needs its own score:

```js
const result = await diagnose({
  projects: [
    { directory: "./modules/billing" },
    {
      directory: "./modules/payroll",
      config: { rules: { "react-doctor/no-danger": "off" } },
    },
  ],
  config: { ignore: { files: ["**/generated/**"] } },
  concurrency: 4,
});

console.log(result.score); // worst score across projects, or null
console.log(result.projects); // ProjectResult[], same order as input
console.log(result.diagnostics); // all diagnostics across projects
```

Projects run through a worker pool. `concurrency` caps how many scan at once (default 4); set it to `1` for sequential runs. Results keep input order.

Each entry in `result.projects` is either `{ ok: true, directory, ...DiagnoseResult }` or `{ ok: false, directory, error }`, so one failing project does not reject the whole batch.

Config layers additively, least to most specific: the project's on-disk `doctor.config.*`, then the batch-level `config`, then the per-project `config`. `rules` and `categories` merge per key, and `ignore` lists union, so a per-project override changes individual rules without discarding the base config.

Project entries also accept the same scan options as `diagnose` (`lint`, `deadCode`, and so on). Per-project values win over batch-level values.

## JSON reports

Convert a result into the same report shape used by `--json`:

```js
const report = toJsonReport(result, {
  version: "1.0.0",
});
```

Summarize diagnostics by severity and category:

```js
const counts = summarizeDiagnostics(result.diagnostics);
```

## Exported types and helpers

`react-doctor/api` exports:

- `diagnose`
- `toJsonReport`
- `summarizeDiagnostics`
- `JsonReport`
- `JsonReportSummary`
- `JsonReportProjectEntry`
- `JsonReportMode`
- `buildJsonReport`
- `buildJsonReportError`

Use the CLI when you want terminal output, PR comments, or install flows. Use the API when you need to embed React Doctor in another tool.