Function parseTypeAndSubtype

lib/internal/mime.js:42–83

(str)

const SEMICOLON = ';';

function parseTypeAndSubtype(str) {
  // Skip only HTTP whitespace from start
  let position = SafeStringPrototypeSearch(str, END_BEGINNING_WHITESPACE);
  // read until '/'
  const typeEnd = StringPrototypeIndexOf(str, SOLIDUS, position);
  const trimmedType = typeEnd === -1 ?
    StringPrototypeSlice(str, position) :
    StringPrototypeSlice(str, position, typeEnd);
  const invalidTypeIndex = SafeStringPrototypeSearch(trimmedType,
                                                     NOT_HTTP_TOKEN_CODE_POINT);
  if (trimmedType === '' || invalidTypeIndex !== -1 || typeEnd === -1) {
    throw new ERR_INVALID_MIME_SYNTAX('type', str, invalidTypeIndex);
  }
  // skip type and '/'
  position = typeEnd + 1;
  const type = toASCIILower(trimmedType);
  // read until ';'
  const subtypeEnd = StringPrototypeIndexOf(str, SEMICOLON, position);
  const rawSubtype = subtypeEnd === -1 ?
    StringPrototypeSlice(str, position) :
    StringPrototypeSlice(str, position, subtypeEnd);
  position += rawSubtype.length;
  if (subtypeEnd !== -1) {
    // skip ';'
    position += 1;
  }
  const trimmedSubtype = StringPrototypeSlice(
    rawSubtype,
    0,
    SafeStringPrototypeSearch(rawSubtype, START_ENDING_WHITESPACE));
  const invalidSubtypeIndex = SafeStringPrototypeSearch(trimmedSubtype,
                                                        NOT_HTTP_TOKEN_CODE_POINT);
  if (trimmedSubtype === '' || invalidSubtypeIndex !== -1) {
    throw new ERR_INVALID_MIME_SYNTAX('subtype', str, invalidSubtypeIndex);
  }
  const subtype = toASCIILower(trimmedSubtype);
  return [
    type,
    subtype,
    position,
  ];
}

const EQUALS_SEMICOLON_OR_END = /[;=]|$/;
const QUOTED_VALUE_PATTERN = /^(?:([\\]$)|[\\][\s\S]|[^"])*(?:(")|$)/u;