Question

我们将应用程序更新到RxJs 6（使用rxjs-compat）时遇到问题。仍在RxJs 5上的引用库使用ErrorObservable作为方法的返回类型。

public handleError(error: Error): ErrorObservable {
    ...
    return Observable.throw('some error message');
}

截至目前，ErrorObservable是RxJs中的非泛型类型： https://github.com/ReactiveX/rxjs/blob/5.5.11/src/observable/ErrorObservable.ts

export class ErrorObservable extends Observable<any> {
  ...
}

这已经改变了RxJs 6
（见https://github.com/ReactiveX/rxjs/blob/master/compat/observable/ErrorObservable.ts）

export class ErrorObservable<T> extends Observable<T> {
  static create<T>(error: any, scheduler?: SchedulerLike) {
    return throwError(error, scheduler);
  }
}

当然会导致编译错误：

ERROR in ... : error TS2314: Generic type 'ErrorObservable<T>' requires 1 type argument(s).

这是rxjs-compat未涵盖的情况，还是rxjs-compat中的类型定义问题？

Answer 1

查看breaking-changes section

所有可观察的课程（https://github.com/ReactiveX/rxjs/tree/5.5.8/src/observable）有从v6中删除，有利于现有或新的运营商执行与类方法相同的操作。例如， ArrayObservable.create(myArray)可以替换from(myArray)，或者fromArray() 新运算符throwError

您似乎应该使用ErrorObservable函数而不是#include <iostream> #include <string> #include <fstream> using namespace std; using std::string; using std::fstream; typedef struct WAV_HEADER { /* for the part of RIEF Chunk Descriptor */ uint8_t RIFF[4]; // RIFF Header Magic header uint32_t ChunkSize; // RIFF Chunk Size uint8_t WAVE[4]; // WAVE Header /* for the part of "fmt" subChunk */ uint8_t fmt[4]; // FMT header uint32_t Subchunk1Size; // Size of the fmt chunk uint16_t AudioFormat; // Audio format 1=PCM,6=mulaw,7=alaw, 257=IBM Mu-Law, 258=IBM A-Law, 259=ADPCM uint16_t NumOfChan; // Number of channels 1=Mono 2=Sterio uint32_t SamplesPerSec; // Sampling Frequency in Hz uint32_t bytesPerSec; // bytes per second uint16_t blockAlign; // 2=16-bit mono, 4=16-bit stereo uint16_t bitsPerSample; // Number of bits per sample /* For the part of "data" subChunk */ uint8_t Subchunk2ID[4]; // "data" string uint32_t Subchunk2Size; // Sampled data length }wav_hdr; int getFileSize(FILE* inFile); int main(int argc, char* argv[]) { wav_hdr wavHeader; int headerSize = sizeof(wav_hdr), filelength = 0; const char* filePath; string input; if (argc <= 1) { cout << "Input wave file name: "; cin >> input; cin.get(); filePath = input.c_str(); } else { filePath = argv[1]; cout << "Input wave file name: " << filePath << endl; } FILE* wavFile = fopen(filePath, "r"); if (wavFile == nullptr) { fprintf(stderr, "Unable to open wave file: %s\n", filePath); return 1; } //Read the header size_t bytesRead = fread(&wavHeader, 1, headerSize, wavFile); cout << "Header Read " << bytesRead << " bytes." << endl; if (bytesRead > 0) { //Read the data uint16_t bytesPerSample = wavHeader.bitsPerSample / 8; //Number of bytes per sample uint64_t numSamples = wavHeader.ChunkSize / bytesPerSample; //How many samples are in the wav file? static const uint16_t BUFFER_SIZE = 4096; int8_t* buffer = new int8_t[BUFFER_SIZE]; while ((bytesRead = fread(buffer, sizeof buffer[0], BUFFER_SIZE / (sizeof buffer[0]), wavFile)) > 0) { /** DO SOMETHING WITH THE WAVE DATA HERE **/ cout << "Read " << bytesRead << " bytes." << endl; } delete [] buffer; buffer = nullptr; filelength = getFileSize(wavFile); cout << "File is :" << filelength << " bytes." << endl; cout << "RIFF header :" << wavHeader.RIFF[0] << wavHeader.RIFF[1] << wavHeader.RIFF[2] << wavHeader.RIFF[3] << endl; cout << "WAVE header :" << wavHeader.WAVE[0] << wavHeader.WAVE[1] << wavHeader.WAVE[2] << wavHeader.WAVE[3] << endl; cout << "FMT :" << wavHeader.fmt[0] << wavHeader.fmt[1] << wavHeader.fmt[2] << wavHeader.fmt[3] << endl; cout << "Data size :" << wavHeader.ChunkSize << endl; // Display the sampling Rate from the header cout << "Sampling Rate :" << wavHeader.SamplesPerSec << endl; cout << "Number of bits used :" << wavHeader.bitsPerSample << endl; cout << "Number of channels :" << wavHeader.NumOfChan << endl; cout << "Number of bytes per second :" << wavHeader.bytesPerSec << endl; cout << "Data length :" << wavHeader.Subchunk2Size << endl; cout << "Audio Format :" << wavHeader.AudioFormat << endl; // Audio format 1=PCM,6=mulaw,7=alaw, 257=IBM Mu-Law, 258=IBM A-Law, 259=ADPCM cout << "Block align :" << wavHeader.blockAlign << endl; cout << "Data string :" << wavHeader.Subchunk2ID[0] << wavHeader.Subchunk2ID[1] << wavHeader.Subchunk2ID[2] << wavHeader.Subchunk2ID[3] << endl; } fclose(wavFile); return 0; } // find the file size int getFileSize(FILE* inFile) { int fileSize = 0; fseek(inFile, 0, SEEK_END); fileSize = ftell(inFile); fseek(inFile, 0, SEEK_SET); return fileSize; }类。

突破RxJs ErrorObservable的变化（迁移5 - > 6）

1 个答案: