Cannot create encoded data

Problem

I cannot get encoded data with a struct param in the test code below.

// TEST CODE

const functionArgs = [
    xxx,
    yyy,
    {
        x: x,
        y: y
    }
]
// console.log(functionArgs.length) => 3

const abi = compiledJSON.abi
const iface = new ethers.utils.Interface(abi)

// console.log(iface.functions.targetFunction) =>
   ...
   inputs:
   [ { internalType: 'string', name: 'title', type: 'string' },
     { internalType: 'string', name: 'name', type: 'string' },
     { components: [Array],
       internalType: 'struct Struct.Str',
       name: 'str',
       type: 'tuple' } ], ...

const calldata = iface.functions.targetFunction.encode(...functionArgs) // Error

Error Message

Error: missing argument in interface function targetFunction (count=2, expectedCount=3, version=4.0.47)

Version

ethers: 4.0.47 solc: 0.5.16 truffle: 5.1.9

[nphsu]

Oh, sorry when changing ...functionArgs into functionArgs, then it works. Thank you for your reviewing!

[nphsu]

Thank you very much for your kindness 😃