Format phone numbers in Google Sheets using Google App Sheet

format-phone-number.gs

function onOpen() {
  var ui = SpreadsheetApp.getUi()
  ui.createMenu('Utilities')
    .addItem('Format Phone Numbers', 'formatPhone')
    .addToUi();
}

function formatPhone() {
  const range = SpreadsheetApp.getActive().getActiveRange()
  const values = range
    .getValues()
    .map(row => row.map(value => {
      let digits = ('' + value).replace(/[^\d]/g, '')
      if (digits.length === 11 && digits[0] === '1') digits = digits.slice(1)
      if (digits.length !== 10) return value
      return `${digits.slice(0, 3)}-${digits.slice(3, 6)}-${digits.slice(6)}`
    }))
  range.setValues(values)
}