Get values from multidimensional object to list-CodePudding

I have object:

data = {
    "usa": {
        "a": {
            "min": 1,
            "max": 2,
            "avg": 1.5
        },
        "b": {
            "min": 3,
            "max": 5,
            "avg": 4
        }
    },
    "canada": {
        "c": {
            "min": 1,
            "max": 2,
            "avg": 1.5
        }
    }
}

I would like receive all max values from second dimension, for example:

function getMaxValues(country: string): number[] {
    const maxValues: number[] = data[country]???

    return maxValues;
}

I any better way than iterate over this object and collect results? In other languages are special functions for this. I don't want use iteration because this object is very large and usually specific functions for this are more efficient.

CodePudding user response：

You need to get the country object values then map to get max value.

let data = {
    "usa": {
        "a": {
            "min": 1,
            "max": 2,
            "avg": 1.5
        },
        "b": {
            "min": 3,
            "max": 5,
            "avg": 4
        }
    },
    "canada": {
        "c": {
            "min": 1,
            "max": 2,
            "avg": 1.5
        }
    }
}

function getMaxValues(country) {
    const maxValues = Object.values(data[country]).map(v => v.max);

    return maxValues;
}

console.log(getMaxValues('usa'));

CodePudding user response：

You can do:

Object.values(data).flatMap((country) => {
   return Object.values(country).map(({max}) => max);
});

CodePudding user response：

You can reduce the entries of the object:

const data = {
    "usa": {
        "a": {
            "min": 1,
            "max": 2,
            "avg": 1.5
        },
        "b": {
            "min": 3,
            "max": 5,
            "avg": 4
        }
    },
    "canada": {
        "c": {
            "min": 1,
            "max": 2,
            "avg": 1.5
        }
    }
};

const maxValuesPerCountry = Object.entries(data)
  .reduce( (acc, [key, value]) => 
    ( {...acc, [key]: Object.entries(value).map(([, v]) => v.max) } ), {} );

console.log(maxValuesPerCountry);

.as-console-wrapper {
    max-height: 100% !important;
}