const reg = /[0-3]/g;
const data = '2020';
console.log(data.matchAll(reg))
console.log([...data.matchAll(reg)])



/**
 * 0: ["2", index: 0, input: "2020", groups: undefined]
 * 1: ["0", index: 1, input: "2020", groups: undefined]
 * 2: ["2", index: 2, input: "2020", groups: undefined]
 * 3: ["0", index: 3, input: "2020", groups: undefined]
 */