react-native-calendars/src/velocityTracker.js

React Native Calendar Components

export class VelocityTracker {
    history;
    lastPosition;
    lastTimestamp;
    constructor() {
        this.history = [];
        this.lastPosition = undefined;
        this.lastTimestamp = undefined;
    }
    add(position) {
        const timestamp = new Date().valueOf();
        if (this.lastPosition && this.lastTimestamp && timestamp > this.lastTimestamp) {
            const diff = position - this.lastPosition;
            if (diff > 0.001 || diff < -0.001) {
                this.history.push(diff / (timestamp - this.lastTimestamp));
            }
        }
        this.lastPosition = position;
        this.lastTimestamp = timestamp;
    }
    estimateSpeed() {
        const finalTrend = this.history.slice(-3);
        const sum = finalTrend.reduce((r, v) => r + v, 0);
        return sum / finalTrend.length;
    }
    reset() {
        this.history = [];
        this.lastPosition = undefined;
        this.lastTimestamp = undefined;
    }
}