overleaf/services/web/scripts/translations/download.js

const { promises: fs } = require('fs')
const oneSky = require('@brainly/onesky-utils')
const sanitizeHtml = require('sanitize-html')
const { withAuth } = require('./config')

async function run() {
  try {
    // The recommended OneSky set-up appears to require an API request to
    // generate files on their side, which you could then request and use. We
    // only have 1 such file that appears to be misnamed (en-US, despite our
    // translations being marked as GB) and very out-of-date.
    // However by requesting the "multilingual file" for this file, we get all
    // of the translations
    const content = await oneSky.getMultilingualFile(
      withAuth({
        fileName: 'en-US.json'
      })
    )
    const json = JSON.parse(content)

    for (const [code, lang] of Object.entries(json)) {
      for (let [key, value] of Object.entries(lang.translation)) {
        // Handle multi-line strings as arrays by joining on newline
        if (Array.isArray(value)) {
          value = value.join('\n')
        }
        lang.translation[key] = sanitize(value)
      }

      const outputLngCode = code === 'en-GB' ? 'en' : code
      await fs.writeFile(
        `${__dirname}/../../locales/${outputLngCode}.json`,
        JSON.stringify(lang.translation, null, 2)
      )
    }
  } catch (error) {
    console.error(error)
    process.exit(1)
  }
}
run()

/**
 * Sanitize a translation string to prevent injection attacks
 *
 * @param {string} input
 * @returns {string}
 */
function sanitize(input) {
  return sanitizeHtml(input, {
    // Allow "replacement" tags (in the format <0>, <1>, <2>, etc) used by
    // react-i18next to allow for HTML insertion via the Trans component.
    // See: https://github.com/overleaf/developer-manual/blob/master/code/translations.md
    // Unfortunately the sanitizeHtml library does not accept regexes or a
    // function for the allowedTags option, so we are limited to a hard-coded
    // number of "replacement" tags.
    allowedTags: ['b', 'strong', 'a', 'code', ...range(10)],
    allowedAttributes: {
      a: ['href', 'class']
    },
    textFilter(text) {
      return text
        .replace(/\{\{/, '&#123;&#123;')
        .replace(/\}\}/, '&#125;&#125;')
    }
  })
}

/**
 * Generate a range of numbers as strings up to the given size
 *
 * @param {number} size Size of range
 * @returns {string[]}
 */
function range(size) {
  return Array.from(Array(size).keys()).map(n => n.toString())
}