TypeError: uniformMap[mu.name] is not a function

CesiumJS
1

hello, i meet the error when i use postProcessStages to simulate the fog with shader, the cesium version is 1.106.1,my code is shown below:

const fog = `
float getDistance(sampler2D depthTexture, vec2 texCoords)
{
    float depth = czm_unpackDepth(texture(depthTexture, texCoords));
    if (depth == 0.0) {
        return czm_infinity;
    }
    vec4 eyeCoordinate = czm_windowToEyeCoordinates(gl_FragCoord.xy, depth);
    return -eyeCoordinate.z / eyeCoordinate.w;
}
float interpolateByDistance(vec4 nearFarScalar, float distance)
{
    float startDistance = nearFarScalar.x;
    float startValue = nearFarScalar.y;
    float endDistance = nearFarScalar.z;
    float endValue = nearFarScalar.w;
    float t = clamp((distance - startDistance) / (endDistance - startDistance), 0.0, 1.0);
    return mix(startValue, endValue, t);
}
vec4 alphaBlend(vec4 sourceColor, vec4 destinationColor)
{
    return sourceColor * vec4(sourceColor.aaa, 1.0) + destinationColor * (1.0 - sourceColor.a);
}
uniform sampler2D colorTexture;
uniform sampler2D depthTexture;
uniform vec4 fogByDistance;
uniform vec4 fogColor;
in vec2 v_textureCoordinates;
void main(void)
{
    float distance = getDistance(depthTexture, v_textureCoordinates);
    vec4 sceneColor = texture(colorTexture, v_textureCoordinates);
    float blendAmount = interpolateByDistance(fogByDistance, distance);
    vec4 finalFogColor = vec4(fogColor.rgb, fogColor.a * blendAmount);
    out_FragColor = alphaBlend(finalFogColor, sceneColor);
}`

function createFogStage() {
    var Fog= new Cesium.PostProcessStage({
        name: 'czm_fog',
        fragmentShader: Fog
    });
    return Fog;
}

var collection = viewer.scene.postProcessStages;
var fog= createFogStage()
collection.add(fog)

look forward to your reply.