expo-face-check

On-device face detection for Expo — detects if an image has exactly one dominant face. Runs entirely on-device with no network calls.

• iOS: Apple Vision framework
• Android: Google ML Kit Face Detection

Installation

npx expo install expo-face-check

Usage

import { checkFace } from 'expo-face-check';

const result = await checkFace(imageUri);

if (result.status === 'READY') {
  // Single dominant face detected
  console.log(result.dominantFaceBounds); // { x, y, width, height }
} else if (result.status === 'NO_FACE') {
  // No face found
} else if (result.status === 'MULTIPLE_FACES') {
  // Multiple faces, none dominant
}

API

checkFace(imageUri: string): Promise<FaceCheckResult>

Analyzes a local image for faces.

Parameters:

• imageUri — Local file URI of the image (e.g., from expo-image-picker)

Returns: FaceCheckResult

type FaceCheckStatus = 'READY' | 'NO_FACE' | 'MULTIPLE_FACES';

interface FaceBounds {
  x: number;
  y: number;
  width: number;
  height: number;
}

interface FaceCheckResult {
  status: FaceCheckStatus;
  faceCount: number;
  dominantFaceBounds?: FaceBounds;
}

Status values

| Status | Meaning | |--------|---------| | READY | Exactly one dominant face detected | | NO_FACE | No faces found in the image | | MULTIPLE_FACES | Multiple faces found, none clearly dominant |

A face is considered "dominant" when it's either the only face, or at least 2x larger than the next biggest face. Faces smaller than 1.5% of the image area are ignored.

License

MIT