primaryAxisSizingMode
Applicable only on auto-layout frames. Determines whether the primary axis has a fixed length (determined by the user) or an automatic length (determined by the layout engine).
Signature
primaryAxisSizingMode: 'FIXED' | 'AUTO'
Remarks
Auto-layout frames have a primary axis, which is the axis that resizes when you add new items into the frame. For example, frames with "VERTICAL" layoutMode resize in the y-axis.
"FIXED": The primary axis length is determined by the user or plugins, unless thelayoutAlignis set to “STRETCH” orlayoutGrowis 1."AUTO": The primary axis length is determined by the size of the children. If set, the auto-layout frame will automatically resize along the counter axis to fit its children.
Note: “AUTO” should not be used in any axes where layoutAlign = “STRETCH” or layoutGrow = 1. Either use “FIXED” or disable layoutAlign/layoutGrow.