Bug(dexie-export-import): importDb data corrupt on non-ASCII string

[cha0sCat]

exportDB works great.

importDB can cause data corruption on non-ascii characters.

For example, if we save '让我们说中文' as string, export & import can make some of the records become '让我们��中文'

Here's the reproducible code:
https://jsfiddle.net/j58xz679/10/

const testDB = new Dexie('testDB')

testDB.version(1).stores({
  testTable: '++id'
})

// generate some test record and insert it
const insertTestData = async () => {
  console.log('start insert test data')

  // const testPattern = 'Lets speak English\n'  // English
  // const testPattern = '日本語を話しましょう\n'  // Japanese
  const testPattern = '让我们说中文\n'  // Chinese
  const data = Array(1000).fill(0).map(() => ({
    content: testPattern.repeat(1000)
  }))
  await testDB.table('testTable').bulkAdd(data)

  console.log('insert test data done', data.length, await testDB.table('testTable').count())
}

// check if there's �� in content (this should not happen)
const checkTestData = async () => {
  console.log('start check test data')

  const data = await testDB
      .table('testTable')
      .toArray()
  const corruptedData = data.filter(record => record.content.includes("��"))
  if (corruptedData.length > 0) {
    console.error('check test data failed, corrupt count: ', corruptedData.length)
    return false
  }

  console.log('check test data done, no corrupt', data.length)
}

const exportAndImportDb = async () => {
  // export and import the db
  // export works OK
  console.log('start export db')
  const data = await exportDB(testDB, {prettyJson: false})
  console.log('export db done')

  // proof that export is ok
  const stringData = await data.text()
  if (stringData.includes('��')) { console.warn('exported data should not contain ��') }

  // !!! this is where the bug happens
  console.log('start import db')
  await importDB(data, {clearTablesBeforeImport: true})
  console.log('import db done')
}

testDB.table('testTable').clear()
    .then(() => insertTestData())
    .then(() => checkTestData())  // this should success (no corrupt)
    .then(() => exportAndImportDb())  // this should cause the data to be corrupt
    .then(() => checkTestData())  // this should fail (corrupt data)