如何 map 我從 api 調用 usestate 變量獲得的 object 數組所需的數據

Question

[
    {
        cases: {new: '+44', active: 216, critical: 1, recovered: 15364, 1M_pop: '35323', …}
        continent: "Asia"
        country: "Brunei"
        day: "2022-01-10"
        deaths: {new: null, 1M_pop: '221', total: 98}
        population: 443851
        tests: {1M_pop: '1562743', total: 693625}
        time: "2022-01-10T16:15:04+00:00"
    },
    { 
        cases: {new: '+2', active: 4, critical: null, recovered: 20, 1M_pop: '34', …}
        continent: "Oceania"
        country: "Solomon-Islands"
        day: "2022-01-10"
        deaths: {new: null, 1M_pop: null, total: null}
        population: 711920
        tests: {1M_pop: '6321', total: 4500}
        time: "2022-01-10T16:15:04+00:00"
    }
]

像這樣，我有 236 個 object 數組，但我只想要它的少數數據，如國家、大陸、總案例等，並將其存儲在 usetate 變量中，該變量將是 object 的數組，但它只會有這個數據

Answer 1

let response = [
    {
        cases: { new: '+44', active: 216, critical: 1, recovered: 15364, 1M_pop: '35323', … }
        continent: "Asia"
        country: "Brunei"
        day: "2022-01-10"
        deaths: { new: null, 1M_pop: '221', total: 98 }
        population: 443851
        tests: { 1M_pop: '1562743', total: 693625 }
        time: "2022-01-10T16:15:04+00:00"
    },
    {
        cases: { new: '+2', active: 4, critical: null, recovered: 20, 1M_pop: '34', … }
        continent: "Oceania"
        country: "Solomon-Islands"
        day: "2022-01-10"
        deaths: { new: null, 1M_pop: null, total: null }
        population: 711920
        tests: { 1M_pop: '6321', total: 4500 }
        time: "2022-01-10T16:15:04+00:00"
    }
];
let mappedResponse = response.map(obj => {
    const { country, continent } = obj;
    return {
        country, 
        continent
    }
})

Answer 2

如果我理解得很好，您有一個包含 236 個條目的數組。 如果這是正確的，您可以執行以下操作：

const results = [
    {
        cases: {new: '+44', active: 216, critical: 1, recovered: 15364, 1M_pop: '35323', …}
        continent: "Asia"
        country: "Brunei"
        day: "2022-01-10"
        deaths: {new: null, 1M_pop: '221', total: 98}
        population: 443851
        tests: {1M_pop: '1562743', total: 693625}
        time: "2022-01-10T16:15:04+00:00"
    },
    { 
        cases: {new: '+2', active: 4, critical: null, recovered: 20, 1M_pop: '34', …}
        continent: "Oceania"
        country: "Solomon-Islands"
        day: "2022-01-10"
        deaths: {new: null, 1M_pop: null, total: null}
        population: 711920
        tests: {1M_pop: '6321', total: 4500}
        time: "2022-01-10T16:15:04+00:00"
    }
];

const newArray = results.map(m => {
   return { country: m.country, cases: m.cases }
})