How to pass device language when registering?

I’m struggling to get the device language to my backend when registering:

In my ClientSide ( Ionic ) , i’m getting the language with this way:


    this.language = localStorage.getItem('language')
    if (this.language === 'ar') {
      this.language = 'Arabic'
    } else {
      this.language = 'English'
    }

But couldn’t figure out how to get it when i’m registering my user, i want to store it in the database

here’s my ServerSide ( Meteor )

async function register(firstname, email, password, password2, next) {

  if (!email) {
    next(null, { error: 'NO_EMAIL', field: 'email' })
  } else if (!password) {
    next(null, { error: 'NO_PASSWORD', field: 'password' })
  } else if (!firstname) {
    next(null, { error: 'NO_FIRSTNAME', field: 'firstname' })
  } else if (typeof (email) !== 'string' || email.length > 100) {
    next(null, { error: 'BAD_EMAIL', field: 'email' })
  } else if (typeof (password) !== 'string' || password.length > 100) {
    next(null, { error: 'BAD_PASSWORD', field: 'password' })
  } else if (typeof (firstname) !== 'string' || firstname.length > 100) {
    next(null, { error: 'BAD_FIRSTNAME', field: 'firstname' })
  } else if (password !== password2) {
    next(null, { error: 'PASSWORDS_NOT_MATCHING', field: 'password' })
  } else {
    const credentials = {
      profile: {
        name: firstname
      },
      email,
      password,
      language
    }
}

Is there a way to pass the language that i’m getting in my localstorage ( clientside ) to the register function ?