function getEncoding(label) {
    // 1. Remove any leading and trailing ASCII whitespace from label.
    label = String(label).trim().toLowerCase();

    // 2. If label is an ASCII case-insensitive match for any of the
    // labels listed in the table below, return the corresponding
    // encoding, and failure otherwise.
    if (Object.prototype.hasOwnProperty.call(label_to_encoding, label)) {
      return label_to_encoding[label];
    }
    return null;
  }
@param {string} label The encoding label.
@return {?{name:string,labels:Array.<string>}}