Vee-Validate mobile number validator (Bangladesh)

mobile.js

import VeeValidate from 'vee-validate';
Vue.use(VeeValidate, { inject: false });
VeeValidate.Validator.extend('mobile', {
    getMessage: field => `The number is not valid for Bangladesh.`,
    validate: value => {
        var strongRegex = new RegExp("^(8801[756891]{1}[0-9]{8}|01[756891]{1}[0-9]{8})$");
        if(value=='') return true;
        return strongRegex.test(value);
    }
});