obstacleDistance() from robotdriver.ts returns NaN

[Bertani545]

This only happens once after initializing the robot but causes some bugs for some programs.
For example, the next code works fine:

robot.onObstacleDistanceChanged(function () {
distance = robot.obstacleDistance()
    if (scanning) {
        if (distance > 15) {
            scanning = 0
            robot.motorTank(30, 30)
        }
    } else {
        if (distance < 15) {
            robot.motorTank(-30, -30)
            robot.motorTank(0, 0)
            robot.motorTank(-25, 25)
            basic.pause(1000)
            scanning = 1
            robot.motorTank(25, -25)
        } else {
            robot.motorTank(30, 30)
        }
    }
})
let scanning = 0
let distance = 0
robot.dfRobotMaqueen.start()

But if I invert the conditional, that single frame where it is NaN makes it such that the robot starts spinning at the beginning of the program.

robot.onObstacleDistanceChanged(function () {
distance = robot.obstacleDistance()
    if (scanning) {
        if (distance > 15) {
            scanning = 0
            robot.motorTank(30, 30)
        }
    } else {
        if (distance > 15) {
            robot.motorTank(30, 30)
        } else {
             robot.motorTank(-30, -30)
            robot.motorTank(0, 0)
            robot.motorTank(-25, 25)
            basic.pause(1000)
            scanning = 1
            robot.motorTank(25, -25)
           
        }
    }
})
let scanning = 0
let distance = 0
robot.dfRobotMaqueen.start()

If I'm not wrong, this could be fixed changing line 45 of the file drivers/kalmanfilter1d.ts to if (isNaN(this.x) || isNaN(this.cov)) {.
I do not make a pull request because I don't know how to test this libraries.