Check array length in object javascript

Question

I have some object like this

    const array = 
    {
      "entities": [
        {
          "annexes": [
            {
              "buildingUniqueIds": []
            },
            {
              "buildingUniqueIds": []
            },
            {
              "buildingUniqueIds": []
            },
          ],
          "buildingUniqueIds": []
        }
      ]
}

I need to check if any of those array is empty to return true, is this possible to do in one iteration, here is what I have tried for now, but some does not check array length it always return true even if array is empty :(

  get haveBuildingUniqueIds(): boolean {
    const condition1 = this.array.entities.some(x => x.annexes.some(y => y.buildingUniqueIds.some));
    const condition2 = this.array.entities.some(x => x.buildingUniqueIds.some);
    return condition1 && condition2;
  }

T.J. Crowder · Accepted Answer · 2021-09-29 10:15:22Z

some is the right method to use, but it's a method, not a flag, so your innermost .some(y => y.buildingUniqueIds.some) will always return true, because a method is a truthy value.

Instead, check length:

const hasEmpties = array.entities.some(({annexes, buildingUniqueIds}) =>
    buildingUniqueIds.length === 0 ||
    annexes.some(({buildingUniqueIds}) => buildingUniqueIds.length === 0)
);

Live Example:

function check(label, array) {
    const hasEmpties = array.entities.some(({annexes, buildingUniqueIds}) =>
        buildingUniqueIds.length === 0 ||
        annexes.some(({buildingUniqueIds}) => buildingUniqueIds.length === 0)
    );
    console.log(label, "=>", hasEmpties);
}

check("all empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": []
                },
                {
                    "buildingUniqueIds": []
                },
                {
                    "buildingUniqueIds": []
                },
            ],
            "buildingUniqueIds": []
        }
    ]
});

check("none empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
            ],
            "buildingUniqueIds": [{}]
        }
    ]
});

check("entities.buildingUniqueIds empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
            ],
            "buildingUniqueIds": []
        }
    ]
});

check("entities.annexes.buildingUniqueIds[1] empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": []
                },
                {
                    "buildingUniqueIds": [{}]
                },
            ],
            "buildingUniqueIds": [{}]
        }
    ]
});

Side note: If you like, you can use !buildingUniqueIds.length rather than buildingUniqueIds.length === 0.

Or without destructuring if you prefer:

const hasEmpties = array.entities.some(entity =>
    entity.buildingUniqueIds.length === 0 ||
    entity.annexes.some(annex => annex.buildingUniqueIds.length === 0)
);

Live Example:

function check(label, array) {
    const hasEmpties = array.entities.some(entity =>
        entity.buildingUniqueIds.length === 0 ||
        entity.annexes.some(annex => annex.buildingUniqueIds.length === 0)
    );
    console.log(label, "=>", hasEmpties);
}

check("all empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": []
                },
                {
                    "buildingUniqueIds": []
                },
                {
                    "buildingUniqueIds": []
                },
            ],
            "buildingUniqueIds": []
        }
    ]
});

check("none empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
            ],
            "buildingUniqueIds": [{}]
        }
    ]
});

check("entities.buildingUniqueIds empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": [{}]
                },
            ],
            "buildingUniqueIds": []
        }
    ]
});

check("entities.annexes.buildingUniqueIds[1] empty", {
    "entities": [
        {
            "annexes": [
                {
                    "buildingUniqueIds": [{}]
                },
                {
                    "buildingUniqueIds": []
                },
                {
                    "buildingUniqueIds": [{}]
                },
            ],
            "buildingUniqueIds": [{}]
        }
    ]
});

@MiomirDancevic - Sorry, missed that that wasn't just another entry in annexes, but it's an easy fix. I've updated the answer.
@MiomirDancevic - That's okay, it just gets shadowed. But you don't have to use destructuring if you don't want to.
@MiomirDancevic - I've updated the answer, but I do recommend reading up on parameter destructuring so you can do it yourself next time.

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