getColor from ros3djs is sending non numeric value

edit

I am trying to display a PointCloud2 into a web interface.

To do that I am using the javascript librairy ros3djs and its object PointCloud2.

I am able to visualize the different point on my interface. However when I want to display the color of this PointCloud2 by using a custom colormap, ros3djs is sending me non numeric value for a lot of point.

Perhaps it is my PointCloud2 msg that is sending non correct value but on RVIZ the point cloud displayed is correct.

The code that I use for the colormap :

colormap = (x) => {
    //console.log(x);
    let rgb;

    // line 54279 de ROS3d nous renvoie une valeur qui n'est pas un nombre parfois et qui explique le manque de couleur
    if(isNaN(x)) {
        rgb = {
            r: 1,
            g: 1,
            b: 1,
            a: 1.0
        };
    } else {
        this._floatColor[0] = x;
        const intColor = new Int32Array(this._floatColor.buffer);
        const colorInt = intColor[0];
        rgb = {
            r: this._rgb_lut[(colorInt >> 16) & 0xff],
            g: this._rgb_lut[(colorInt >> 8) & 0xff],
            b: this._rgb_lut[(colorInt) & 0xff],
            a: 1.0
        };
    }
    return rgb;
}

Do you know what could be the source of those non numeric value for colors ?