Янковиц,
<script>
let f = a => /\{[^}]+?\}/.test(a);
let r = a => new RegExp(a.slice(2,-2));
let reg ='+1({/[1-9]/}00) 000 000{/[1-9]/}';
reg = reg.match(/(\{[^}]+?\})|(\+)|([()])|(\d)|(\s+)/g);
reg = reg.map(a => a === '0' ? /\d/ : f(a) ? r(a) : a)
document.write(reg)
</script>