How to customize only the color attribute with shaderMaterial?


I have an object using a meshLambertMaterial. I want to customize the color attribute using a shader material, but I still want to keep the other attributes, positions, uv, normals, and index. If I understand this correctly, if I create a shaderMaterial, I will not have access to those attributes.
How can I customize the color attribute while keeping the others?

You will have access to all attributes, unless you use RawShaderMaterial, this is an example of customizing only color with ShaderMaterial: