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javascriptjestjs

Jest how to test a map contents i.e. key and value

I have an JSON object which has a map as follows:

{"name": "Bertha", [["id", "123"], ["status", "active"]]}

Please note that I am representing the map like it would be represented in typescript but I don't know how it would be represented in the underlying Jest framework. It is failing when I use the isEqual([["id", "123"....]) syntax. It is reporting that it received:

Map {"id" => "123", "status" => "active"}

which I find quite confusing.

How do I test the key, value pairs using Jest?

Solution

  • This

    [["id", "123"], ["status", "active"]]

    is an array of arrays, not a Map.

    This

    Map {"id" => "123", "status" => "active"}

    is the conventional syntax for a Map, which would be constructed by passing the array of arrays above into new Map.

    Since it looks like what you actually have is a Map, not an array of arrays - to test that the map's key-values are as above, I'd take the Map's entries (to turn it from a Map back into an array of arrays). Then that structure can be deep checked with toEqual.

    const entries = [...map.entries()];
expect(entries).toEqual([["id", "123"], ["status", "active"]]);

    The other option (which wouldn't be very sustainable if you had many items in the Map) would be to check each one individually.

    expect(map.get('id')).toBe(123);
expect(map.get('status')).toBe('active');