Method performDecode

src/Encoder/Punycode.js:97–124

* Performs decode on given content. * @protected * @param {Chain} content * @return {number[]|string|Uint8Array|Chain|Promise} Decoded content

(content)

   * @return {number[]|string|Uint8Array|Chain|Promise} Decoded content
   */
  async performDecode (content) {
    // Check if the given input contains any unexpected non-basic code points
    const nonBasicIndex = this._nonBasicCodePointIndex(content.getCodePoints())
    if (nonBasicIndex !== -1) {
      throw new InvalidInputError(
        `Invalid Punycode character at index ${nonBasicIndex}`)
    }

    // Split domain into labels
    const labels = content.split('.')
    const decodedParts = new Array(labels.length)

    // Decode each part separately
    for (let i = 0; i < labels.length; i++) {
      // Check for the IDNA prefix
      if (labels[i].indexOf(prefix) !== 0) {
        // Return the part as is
        decodedParts[i] = labels[i]
      } else {
        // Remove IDNA prefix and decode part using Bootstring
        const part = labels[i].substr(prefix.length)
        decodedParts[i] = await this._bootstringEncoder.decode(part)
      }
    }

    // Stick domain labels back together
    return Chain.join(decodedParts, '.')
  }

  /**
   * Returns the first non-basic code point, if any.