VN phone carriers detector

phone-carriers.js

const MOBILE_REGEXP = /^(\+84|0)(3[2-9]|5[2689]|7[06-9]|8[1-5])[0-9]{7}$/
const PREFIX_CARRIERS = {
  viettel: ["32","33","34","35","36","37","38","39"],
  mobifone: ["70","79","77","76","78"],
  vinaphone: ["83","84","85","81","82"],
  vietnamobile: ["52","56","58"],
  gmobile: ["59"]
};

function phoneCarrier(phone) {
  const matches = (phone || '').match(MOBILE_REGEXP)
  if (matches !== null) {
    return Object.keys(PREFIX_CARRIERS)
      .find(prefix => PREFIX_CARRIERS[prefix].includes(matches[2]))
  }
}