react-webcam-qr-scanner
Version:
A humble implementation of a real-time QR-code scanner using WebRTC
193 lines (158 loc) • 7.52 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.useDecoder = void 0;
var _react = _interopRequireDefault(require("react"));
var _WorkerInterface = _interopRequireDefault(require("./WorkerInterface"));
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }
function asyncGeneratorStep(gen, resolve, reject, _next, _throw, key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { Promise.resolve(value).then(_next, _throw); } }
function _asyncToGenerator(fn) { return function () { var self = this, args = arguments; return new Promise(function (resolve, reject) { var gen = fn.apply(self, args); function _next(value) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "next", value); } function _throw(err) { asyncGeneratorStep(gen, resolve, reject, _next, _throw, "throw", err); } _next(undefined); }); }; }
function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }
function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }
function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }
function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }
function _iterableToArrayLimit(arr, i) { if (typeof Symbol === "undefined" || !(Symbol.iterator in Object(arr))) return; var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }
function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }
var DecoderState = {
Pending: "pending",
Worker: "worker",
Fallback: "fallback",
MainThread: "main-thread",
Failed: "failed"
};
var DecoderDefault = {
decode: function decode() {
return Promise.resolve(null);
}
};
var useDecoder = function useDecoder(_ref) {
var askTimeout = _ref.askTimeout,
onLoad = _ref.onLoad;
var jsQR = _react["default"].useRef(null);
var _React$useState = _react["default"].useState(0),
_React$useState2 = _slicedToArray(_React$useState, 2),
exceptions = _React$useState2[0],
setExceptions = _React$useState2[1];
var _React$useState3 = _react["default"].useState(DecoderState.Pending),
_React$useState4 = _slicedToArray(_React$useState3, 2),
state = _React$useState4[0],
setState = _React$useState4[1];
var worker = _react["default"].useMemo(function () {
if (typeof Worker !== "undefined") {
return new _WorkerInterface["default"]();
} else {
console.warn("Failed to start a Web Worker");
return null;
}
}, [exceptions]);
var decoder = _react["default"].useMemo(function () {
switch (state) {
case DecoderState.Worker:
return {
decode: function () {
var _decode = _asyncToGenerator( /*#__PURE__*/regeneratorRuntime.mark(function _callee(imageData) {
return regeneratorRuntime.wrap(function _callee$(_context) {
while (1) {
switch (_context.prev = _context.next) {
case 0:
_context.prev = 0;
_context.next = 3;
return worker.requestDecoding(imageData);
case 3:
return _context.abrupt("return", _context.sent);
case 6:
_context.prev = 6;
_context.t0 = _context["catch"](0);
setExceptions(function (e) {
return e + 1;
});
return _context.abrupt("return", null);
case 10:
case "end":
return _context.stop();
}
}
}, _callee, null, [[0, 6]]);
}));
function decode(_x) {
return _decode.apply(this, arguments);
}
return decode;
}()
};
case DecoderState.MainThread:
return {
decode: function decode(imageData) {
try {
var data = imageData.data,
width = imageData.width,
height = imageData.height;
var result = jsQR.current(data, width, height);
return Promise.resolve(result);
} catch (err) {
console.warn(err);
setExceptions(function (e) {
return e + 1;
});
return Promise.resolve(null);
}
}
};
default:
return DecoderDefault;
}
}, [state, worker, jsQR.current]);
var onInit = _react["default"].useCallback( /*#__PURE__*/_asyncToGenerator( /*#__PURE__*/regeneratorRuntime.mark(function _callee2() {
var loadableJsQR;
return regeneratorRuntime.wrap(function _callee2$(_context2) {
while (1) {
switch (_context2.prev = _context2.next) {
case 0:
_context2.prev = 0;
_context2.next = 3;
return worker.ack(askTimeout);
case 3:
setState(DecoderState.Worker);
typeof onLoad == "function" && onLoad(DecoderState.Worker);
_context2.next = 24;
break;
case 7:
_context2.prev = 7;
_context2.t0 = _context2["catch"](0);
console.warn("Qr decoding worker does not respond. Trying to setup decoding in the main thread...");
setState(DecoderState.Fallback);
_context2.prev = 11;
_context2.next = 14;
return import("jsqr");
case 14:
loadableJsQR = _context2.sent;
jsQR.current = loadableJsQR["default"];
setState(DecoderState.MainThread);
typeof onLoad == "function" && onLoad(DecoderState.MainThread);
_context2.next = 24;
break;
case 20:
_context2.prev = 20;
_context2.t1 = _context2["catch"](11);
console.error("Failed to load script.", _context2.t1);
setState(DecoderState.Failed);
case 24:
case "end":
return _context2.stop();
}
}
}, _callee2, null, [[0, 7], [11, 20]]);
})), [worker]);
_react["default"].useEffect(function () {
onInit();
return function () {
if (worker !== null) {
worker.onDestroy();
setState(DecoderState.Pending);
}
};
}, [worker]);
return decoder;
};
exports.useDecoder = useDecoder;