Function contextFetch

src/fetch.ts:42–138

(context: Context, options: ContextFetchOptions)

}

export function contextFetch(context: Context, options: ContextFetchOptions): Promise<string> {
  const { url: rawUrl, requestType = 'text', responseType = 'text', imageDom } = options
  let url = rawUrl

  const {
    timeout,
    acceptOfImage,
    requests,
    fetchFn,
    fetch: {
      requestInit,
      bypassingCache,
      placeholderImage,
    },
    font,
    workers,
    fontFamilies,
  } = context

  if (requestType === 'image' && (IN_SAFARI || IN_FIREFOX)) {
    context.drawImageCount++
  }

  let request = requests.get(rawUrl)
  if (!request) {
    // cache bypass so we dont have CORS issues with cached images
    // ref: https://developer.mozilla.org/en/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest#Bypassing_the_cache
    if (bypassingCache) {
      if (bypassingCache instanceof RegExp && bypassingCache.test(url)) {
        url += (/\?/.test(url) ? '&' : '?') + new Date().getTime()
      }
    }

    // Font minify
    const canFontMinify = requestType.startsWith('font') && font && font.minify
    const fontTexts = new Set()
    if (canFontMinify) {
      const families = requestType.split(';')[1].split(',')
      families.forEach((family) => {
        if (!fontFamilies.has(family))
          return
        fontFamilies.get(family)!.forEach(text => fontTexts.add(text))
      })
    }
    const needFontMinify = canFontMinify && fontTexts.size

    const baseFetchOptions: BaseFetchOptions = {
      url,
      timeout,
      responseType: needFontMinify ? 'arrayBuffer' : responseType,
      headers: requestType === 'image' ? { accept: acceptOfImage } : undefined,
      ...requestInit,
    }

    request = {
      type: requestType,
      resolve: undefined,
      reject: undefined,