GarageServer.IO/example/shared/core.js

(function(exports){

   exports.getNewState = function (state, inputs, deltaTime) {
       var i = 0;

        if (!state.x && !state.y) {
           state.x = 0;
           state.y = 0;
        }
        for (i = 0; i < inputs.length; i ++) {
            if (inputs[i].input === 'left') {
                state.x -= (50 * deltaTime);
            } else if (inputs[i].input === 'right') {
                state.x += (50 * deltaTime);
            } else if (inputs[i].input === 'down') {
                state.y += (50 * deltaTime);
            } else if (inputs[i].input === 'up') {
                state.y -= (50 * deltaTime);
            }
        }
        return state;
    };
    
    exports.getInterpolatedState = function (previousState, targetState, amount) {
        var interpolationState = {};
        interpolationState.x = (previousState.x + amount * (targetState.x - previousState.x));
        interpolationState.y = (previousState.y + amount * (targetState.y - previousState.y));
        return interpolationState;
    };

})(typeof exports === 'undefined' ? window.GamePhysics = {} : exports);