rep-counter

Zero-dependency rep counting engine for pose detection. Works with any pose model (MediaPipe, MoveNet, PoseNet) on Node.js, web, and React Native.

Installation

npm install rep-counter

Usage

import { countReps, reset, getCount } from 'rep-counter';

// Call with each frame from your pose detector
const result = countReps(pose, 'push-ups');
// → { repCount: 5, state: 'UP', feedback: 'Rep 5!' }

// Reset for new set
reset('push-ups');

// Get current count
getCount('push-ups'); // → 0

API

countReps(pose, exerciseName)

Processes a single frame from pose detection and returns rep count.

Parameters:

• pose — Object with keypoints array (from pose detector)
• exerciseName — Exercise name string

Returns:

{
  repCount: number;   // Current rep count
  state: string;    // 'WAITING', 'DOWN', 'UP', etc.
  feedback: string; // Form feedback
  angle?: number;   // Calculated angle (debugging)
}

reset(exerciseName)

Clears rep count for an exercise to start a new set.

getCount(exerciseName)

Returns current rep count for an exercise.

Supported Exercises

• Push-ups (and variations: incline, decline)
• Squats (and jump squats)
• Pull-ups / Chin-ups
• Dips
• Burpees
• Sit-ups
• Lunges
• Mountain Climbers
• Jumping Jacks

Pose Format

Works with any pose detector that outputs keypoints in this format:

const pose = {
  keypoints: [
    { name: 'left_shoulder', x: 0.5, y: 0.3, score: 0.9 },
    { name: 'left_elbow', x: 0.5, y: 0.5, score: 0.9 },
    { name: 'left_wrist', x: 0.5, y: 0.7, score: 0.9 },
    // ... more keypoints
  ]
};

Keypoint names follow MediaPipe convention: left_shoulder, right_shoulder, left_elbow, left_wrist, left_hip, left_knee, left_ankle, nose, etc.

TypeScript

Fully typed. Import types:

import { Pose, CountResult } from 'rep-counter';

License

MIT