Question

console.log(books[0]._id);
console.log(user.bookRecomendations);
const index = user.bookRecomendations.findIndex( x => x.bookId === books[0]._id);
console.log(index);

它在控制台中返回：

5b0685e238e2e50ba4c10d49

[{"bookId":"5b0685e238e2e50ba4c10d49","rating":900},{"bookId":"5b0949a3b7c9170be08aa6b5","rating":900},{"bookId":"5b0708dbf1079d0dfa98489b","rating":900},{"bookId":"5b0948947c110b0ba9069327","rating":1600}]

-1

as user.bookRecomendations [0] .bookId与book [0]具有相同的值._ id它应该返回0，但它仍然没有，并且显示-1，因为它不匹配。任何建议如何修复它并得到user.bookRecomendations的索引，bookId等于books [0] ._ id？

编辑：

console.log('['+books[0]._id+']');
console.log('['+user.bookRecomendations[0].bookId+']’);
console.log(books[0]._id===user.bookRecomendations[0].bookId);

返回：

[5b0685e238e2e50ba4c10d49]
[5b0685e238e2e50ba4c10d49]
false

Answer 1

好的，问题在于类型，书籍[0] ._ id和user.bookRecomendations [0] .bookId都是对象。所以比较

books[0]._id.toString() === user.bookRecomendations[0].bookId.toString()

完美运作

findIndex返回-1，但它应该返回0

1 个答案: