千分位转数字，数字转千分位

<script>

        class strNumSwitch {

            // 千分转数字

            static toNum = (param) => {

                let num = param

                if (`${param}`.includes(',')) {

                num = param.replace(/(,*)/g, '')

                }

                if (isNaN(Number(num))) {

                num = 0

                }

                return Number(num)

            }

            // 数字转千分

            static toStr = (param) => {

                const str = param.replace(/(,*)/g, '')

                const num = `${str}`.replace(/B(?=(d{3})+(?!d))/g, ',')

                return num

            }

        }

    </script>