react-native-gesture-handler/lib/typescript/handlers/gestures/pinchGesture.js

Declarative API exposing native platform touch and gesture system to React Native

import { ContinousBaseGesture } from './gesture';
function changeEventCalculator(current, previous) {
    'worklet';
    let changePayload;
    if (previous === undefined) {
        changePayload = {
            scaleChange: current.scale,
        };
    }
    else {
        changePayload = {
            scaleChange: current.scale / previous.scale,
        };
    }
    return { ...current, ...changePayload };
}
export class PinchGesture extends ContinousBaseGesture {
    constructor() {
        super();
        this.handlerName = 'PinchGestureHandler';
    }
    onChange(callback) {
        // @ts-ignore TS being overprotective, PinchGestureHandlerEventPayload is Record
        this.handlers.changeEventCalculator = changeEventCalculator;
        return super.onChange(callback);
    }
}