CODEWITHSUNDEEP
javascript
Luca S.
Luca S.

Reputation: 1162

How to check if array contains instance of an object in Javascript?

I have an object like this:

MyLibrary {
  books: 
   [ Book {
      bookType: 'romance'
     } 
  ]
}

Book is a class.

I would like to write a test to check if books contain an object that is an instance of Book. I was expecting to use something like MyLibrary.books.indexOf('Book') but it returns -1 even when Book exist.

Upvotes: 2

Views: 1739

Answers (1)

Alberto Trindade Tavares
Alberto Trindade Tavares

Reputation: 10366

You literally have instanceof:

var hasBook = books.some((book) => book instanceof Book);

Upvotes: 6

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