function functionFunction(...str) {
function getStr(fn, ...arg) {
let fnLen = fn.length
let argLen = arg.length
if (fnLen > argLen) {
return function (...args) {
return getStr(fn, ...arg, ...args)
}
} else {
return fn(...arg)
}
}
function strSum(a, b) {
let arr = arguments
return Array.prototype.join.call(arr, ', ')
}
return getStr(strSum,...str)
}