eventsource-parser/dist/index.cjs.map

Streaming, source-agnostic EventSource/Server-Sent Events parser

{"version":3,"file":"index.cjs","sources":["../src/errors.ts","../src/parse.ts"],"sourcesContent":["/**\n * The type of error that occurred.\n * @public\n */\nexport type ErrorType = 'invalid-retry' | 'unknown-field'\n\n/**\n * Error thrown when encountering an issue during parsing.\n *\n * @public\n */\nexport class ParseError extends Error {\n  /**\n   * The type of error that occurred.\n   */\n  type: ErrorType\n\n  /**\n   * In the case of an unknown field encountered in the stream, this will be the field name.\n   */\n  field?: string\n\n  /**\n   * In the case of an unknown field encountered in the stream, this will be the value of the field.\n   */\n  value?: string\n\n  /**\n   * The line that caused the error, if available.\n   */\n  line?: string\n\n  constructor(\n    message: string,\n    options: {type: ErrorType; field?: string; value?: string; line?: string},\n  ) {\n    super(message)\n    this.name = 'ParseError'\n    this.type = options.type\n    this.field = options.field\n    this.value = options.value\n    this.line = options.line\n  }\n}\n","/**\n * EventSource/Server-Sent Events parser\n * @see https://html.spec.whatwg.org/multipage/server-sent-events.html\n */\nimport {ParseError} from './errors.ts'\nimport type {EventSourceParser, ParserCallbacks} from './types.ts'\n\n// eslint-disable-next-line @typescript-eslint/no-unused-vars\nfunction noop(_arg: unknown) {\n  // intentional noop\n}\n\n/**\n * Creates a new EventSource parser.\n *\n * @param callbacks - Callbacks to invoke on different parsing events:\n *   - `onEvent` when a new event is parsed\n *   - `onError` when an error occurs\n *   - `onRetry` when a new reconnection interval has been sent from the server\n *   - `onComment` when a comment is encountered in the stream\n *\n * @returns A new EventSource parser, with `parse` and `reset` methods.\n * @public\n */\nexport function createParser(callbacks: ParserCallbacks): EventSourceParser {\n  if (typeof callbacks === 'function') {\n    throw new TypeError(\n      '`callbacks` must be an object, got a function instead. Did you mean `{onEvent: fn}`?',\n    )\n  }\n\n  const {onEvent = noop, onError = noop, onRetry = noop, onComment} = callbacks\n\n  let incompleteLine = ''\n\n  let isFirstChunk = true\n  let id: string | undefined\n  let data = ''\n  let eventType = ''\n\n  function feed(newChunk: string) {\n    // Strip any UTF8 byte order mark (BOM) at the start of the stream\n    const chunk = isFirstChunk ? newChunk.replace(/^\\xEF\\xBB\\xBF/, '') : newChunk\n\n    // If there was a previous incomplete line, append it to the new chunk,\n    // so we may process it together as a new (hopefully complete) chunk.\n    const [complete, incomplete] = splitLines(`${incompleteLine}${chunk}`)\n\n    for (const line of complete) {\n      parseLine(line)\n    }\n\n    incompleteLine = incomplete\n    isFirstChunk = false\n  }\n\n  function parseLine(line: string) {\n    // If the line is empty (a blank line), dispatch the event\n    if (line === '') {\n      dispatchEvent()\n      return\n    }\n\n    // If the line starts with a U+003A COLON character (:), ignore the line.\n    if (line.startsWith(':')) {\n      if (onComment) {\n        onComment(line.slice(line.startsWith(': ') ? 2 : 1))\n      }\n      return\n    }\n\n    // If the line contains a U+003A COLON character (:)\n    const fieldSeparatorIndex = line.indexOf(':')\n    if (fieldSeparatorIndex !== -1) {\n      // Collect the characters on the line before the first U+003A COLON character (:),\n      // and let `field` be that string.\n      const field = line.slice(0, fieldSeparatorIndex)\n\n      // Collect the characters on the line after the first U+003A COLON character (:),\n      // and let `value` be that string. If value starts with a U+0020 SPACE character,\n      // remove it from value.\n      const offset = line[fieldSeparatorIndex + 1] === ' ' ? 2 : 1\n      const value = line.slice(fieldSeparatorIndex + offset)\n\n      processField(field, value, line)\n      return\n    }\n\n    // Otherwise, the string is not empty but does not contain a U+003A COLON character (:)\n    // Process the field using the whole line as the field name, and an empty string as the field value.\n    // 👆 This is according to spec. That means that a line that has the value `data` will result in\n    // a newline being added to the current `data` buffer, for instance.\n    processField(line, '', line)\n  }\n\n  function processField(field: string, value: string, line: string) {\n    // Field names must be compared literally, with no case folding performed.\n    switch (field) {\n      case 'event':\n        // Set the `event type` buffer to field value\n        eventType = value\n        break\n      case 'data':\n        // Append the field value to the `data` buffer, then append a single U+000A LINE FEED(LF)\n        // character to the `data` buffer.\n        data = `${data}${value}\\n`\n        break\n      case 'id':\n        // If the field value does not contain U+0000 NULL, then set the `ID` buffer to\n        // the field value. Otherwise, ignore the field.\n        id = value.includes('\\0') ? undefined : value\n        break\n      case 'retry':\n        // If the field value consists of only ASCII digits, then interpret the field value as an\n        // integer in base ten, and set the event stream's reconnection time to that integer.\n        // Otherwise, ignore the field.\n        if (/^\\d+$/.test(value)) {\n          onRetry(parseInt(value, 10))\n        } else {\n          onError(\n            new ParseError(`Invalid \\`retry\\` value: \"${value}\"`, {\n              type: 'invalid-retry',\n              value,\n              line,\n            }),\n          )\n        }\n        break\n      default:\n        // Otherwise, the field is ignored.\n        onError(\n          new ParseError(\n            `Unknown field \"${field.length > 20 ? `${field.slice(0, 20)}…` : field}\"`,\n            {type: 'unknown-field', field, value, line},\n          ),\n        )\n        break\n    }\n  }\n\n  function dispatchEvent() {\n    const shouldDispatch = data.length > 0\n    if (shouldDispatch) {\n      onEvent({\n        id,\n        event: eventType || undefined,\n        // If the data buffer's last character is a U+000A LINE FEED (LF) character,\n        // then remove the last character from the data buffer.\n        data: data.endsWith('\\n') ? data.slice(0, -1) : data,\n      })\n    }\n\n    // Reset for the next event\n    id = undefined\n    data = ''\n    eventType = ''\n  }\n\n  function reset(options: {consume?: boolean} = {}) {\n    if (incompleteLine && options.consume) {\n      parseLine(incompleteLine)\n    }\n\n    isFirstChunk = true\n    id = undefined\n    data = ''\n    eventType = ''\n    incompleteLine = ''\n  }\n\n  return {feed, reset}\n}\n\n/**\n * For the given `chunk`, split it into lines according to spec, and return any remaining incomplete line.\n *\n * @param chunk - The chunk to split into lines\n * @returns A tuple containing an array of complete lines, and any remaining incomplete line\n * @internal\n */\nfunction splitLines(chunk: string): [complete: Array<string>, incomplete: string] {\n  /**\n   * According to the spec, a line is terminated by either:\n   * - U+000D CARRIAGE RETURN U+000A LINE FEED (CRLF) character pair\n   * - a single U+000A LINE FEED(LF) character not preceded by a U+000D CARRIAGE RETURN(CR) character\n   * - a single U+000D CARRIAGE RETURN(CR) character not followed by a U+000A LINE FEED(LF) character\n   */\n  const lines: Array<string> = []\n  let incompleteLine = ''\n  let searchIndex = 0\n\n  while (searchIndex < chunk.length) {\n    // Find next line terminator\n    const crIndex = chunk.indexOf('\\r', searchIndex)\n    const lfIndex = chunk.indexOf('\\n', searchIndex)\n\n    // Determine line end\n    let lineEnd = -1\n    if (crIndex !== -1 && lfIndex !== -1) {\n      // CRLF case\n      lineEnd = Math.min(crIndex, lfIndex)\n    } else if (crIndex !== -1) {\n      lineEnd = crIndex\n    } else if (lfIndex !== -1) {\n      lineEnd = lfIndex\n    }\n\n    // Extract line if terminator found\n    if (lineEnd === -1) {\n      // No terminator found, rest is incomplete\n      incompleteLine = chunk.slice(searchIndex)\n      break\n    } else {\n      const line = chunk.slice(searchIndex, lineEnd)\n      lines.push(line)\n\n      // Move past line terminator\n      searchIndex = lineEnd + 1\n      if (chunk[searchIndex - 1] === '\\r' && chunk[searchIndex] === '\\n') {\n        searchIndex++\n      }\n    }\n  }\n\n  return [lines, incompleteLine]\n}\n"],"names":[],"mappings":";;AAWO,MAAM,mBAAmB,MAAM;AAAA,EAqBpC,YACE,SACA,SACA;AACA,UAAM,OAAO,GACb,KAAK,OAAO,cACZ,KAAK,OAAO,QAAQ,MACpB,KAAK,QAAQ,QAAQ,OACrB,KAAK,QAAQ,QAAQ,OACrB,KAAK,OAAO,QAAQ;AAAA,EACtB;AACF;ACnCA,SAAS,KAAK,MAAe;AAE7B;AAcO,SAAS,aAAa,WAA+C;AAC1E,MAAI,OAAO,aAAc;AACvB,UAAM,IAAI;AAAA,MACR;AAAA,IAAA;AAIE,QAAA,EAAC,UAAU,MAAM,UAAU,MAAM,UAAU,MAAM,UAAa,IAAA;AAEpE,MAAI,iBAAiB,IAEjB,eAAe,IACf,IACA,OAAO,IACP,YAAY;AAEhB,WAAS,KAAK,UAAkB;AAE9B,UAAM,QAAQ,eAAe,SAAS,QAAQ,iBAAiB,EAAE,IAAI,UAI/D,CAAC,UAAU,UAAU,IAAI,WAAW,GAAG,cAAc,GAAG,KAAK,EAAE;AAErE,eAAW,QAAQ;AACjB,gBAAU,IAAI;AAGhB,qBAAiB,YACjB,eAAe;AAAA,EACjB;AAEA,WAAS,UAAU,MAAc;AAE/B,QAAI,SAAS,IAAI;AACD;AACd;AAAA,IACF;AAGI,QAAA,KAAK,WAAW,GAAG,GAAG;AACpB,mBACF,UAAU,KAAK,MAAM,KAAK,WAAW,IAAI,IAAI,IAAI,CAAC,CAAC;AAErD;AAAA,IACF;AAGM,UAAA,sBAAsB,KAAK,QAAQ,GAAG;AAC5C,QAAI,wBAAwB,IAAI;AAG9B,YAAM,QAAQ,KAAK,MAAM,GAAG,mBAAmB,GAKzC,SAAS,KAAK,sBAAsB,CAAC,MAAM,MAAM,IAAI,GACrD,QAAQ,KAAK,MAAM,sBAAsB,MAAM;AAExC,mBAAA,OAAO,OAAO,IAAI;AAC/B;AAAA,IACF;AAMa,iBAAA,MAAM,IAAI,IAAI;AAAA,EAC7B;AAES,WAAA,aAAa,OAAe,OAAe,MAAc;AAEhE,YAAQ,OAAO;AAAA,MACb,KAAK;AAES,oBAAA;AACZ;AAAA,MACF,KAAK;AAGI,eAAA,GAAG,IAAI,GAAG,KAAK;AAAA;AACtB;AAAA,MACF,KAAK;AAGH,aAAK,MAAM,SAAS,IAAI,IAAI,SAAY;AACxC;AAAA,MACF,KAAK;AAIC,gBAAQ,KAAK,KAAK,IACpB,QAAQ,SAAS,OAAO,EAAE,CAAC,IAE3B;AAAA,UACE,IAAI,WAAW,6BAA6B,KAAK,KAAK;AAAA,YACpD,MAAM;AAAA,YACN;AAAA,YACA;AAAA,UAAA,CACD;AAAA,QAAA;AAGL;AAAA,MACF;AAEE;AAAA,UACE,IAAI;AAAA,YACF,kBAAkB,MAAM,SAAS,KAAK,GAAG,MAAM,MAAM,GAAG,EAAE,CAAC,WAAM,KAAK;AAAA,YACtE,EAAC,MAAM,iBAAiB,OAAO,OAAO,KAAI;AAAA,UAC5C;AAAA,QAAA;AAEF;AAAA,IACJ;AAAA,EACF;AAEA,WAAS,gBAAgB;AACA,SAAK,SAAS,KAEnC,QAAQ;AAAA,MACN;AAAA,MACA,OAAO,aAAa;AAAA;AAAA;AAAA,MAGpB,MAAM,KAAK,SAAS;AAAA,CAAI,IAAI,KAAK,MAAM,GAAG,EAAE,IAAI;AAAA,IAAA,CACjD,GAIH,KAAK,QACL,OAAO,IACP,YAAY;AAAA,EACd;AAES,WAAA,MAAM,UAA+B,IAAI;AAC5C,sBAAkB,QAAQ,WAC5B,UAAU,cAAc,GAG1B,eAAe,IACf,KAAK,QACL,OAAO,IACP,YAAY,IACZ,iBAAiB;AAAA,EACnB;AAEO,SAAA,EAAC,MAAM;AAChB;AASA,SAAS,WAAW,OAA8D;AAOhF,QAAM,QAAuB,CAAA;AACzB,MAAA,iBAAiB,IACjB,cAAc;AAEX,SAAA,cAAc,MAAM,UAAQ;AAE3B,UAAA,UAAU,MAAM,QAAQ,MAAM,WAAW,GACzC,UAAU,MAAM,QAAQ;AAAA,GAAM,WAAW;AAG/C,QAAI,UAAU;AAWd,QAVI,YAAY,MAAM,YAAY,KAEhC,UAAU,KAAK,IAAI,SAAS,OAAO,IAC1B,YAAY,KACrB,UAAU,UACD,YAAY,OACrB,UAAU,UAIR,YAAY,IAAI;AAED,uBAAA,MAAM,MAAM,WAAW;AACxC;AAAA,IAAA,OACK;AACL,YAAM,OAAO,MAAM,MAAM,aAAa,OAAO;AAC7C,YAAM,KAAK,IAAI,GAGf,cAAc,UAAU,GACpB,MAAM,cAAc,CAAC,MAAM,QAAQ,MAAM,WAAW,MAAM;AAAA,KAC5D;AAAA,IAEJ;AAAA,EACF;AAEO,SAAA,CAAC,OAAO,cAAc;AAC/B;;;"}