How can I properly update a specific line item property in my cart?

[hazzardt]

Been trying to find something which would work but am unable to. I want to update a specific line item property, in my cart. My quantity editor works just fine but this seems to have a different approach. I tried using this piece of code:

"properties" : {"Font": "Arial"}

But it seems to replace all the properties with just this one, instead of editing existing "Font" property. What am I missing? Can anyone point me into the rig

[Jason]

Line item properties work with strings, and you're not passing one here. Any reason why you couldn't pass something like "Font:Arial"?