javascript - 如何将 JSON 响应的特定元素插入数组？

Question

这个问题已经有答案了:

From an array of objects, extract value of a property as array (25 个回答)

已关闭 4 年前。

我正在使用 Nomics 加密货币 API。这是 Axios 调用:

axios.get(apiURL + apiKey + apiSpecs)
.then(function (response) {
  // sort data by highest market cap
  console.log(response.data)
})

以及相应的 JSON 响应:

[{ circulating_supply: '70126880',
    high: '7.18687000',
    high_timestamp: '2018-01-05T00:00:00.000Z',
    market_cap: '58767727.57',
    max_supply: '100000000',
    price: '0.83802000',
    price_date: '2019-04-08',
    currency: 'ETP',
    rank: '96' },
  { circulating_supply: '350000000',
    high: '2.83125000',
    high_timestamp: '2018-01-10T00:00:00.000Z',
    market_cap: '54558000.00',
    max_supply: null,
    price: '0.15588000',
    price_date: '2019-04-08',
    currency: 'QASH',
    rank: '97' }, 
... ]

如何返回仅包含货币属性的数组，例如 var arr = [ETP, QASH, ...]

Answer 1

使用 map :

const response = [{
    circulating_supply: '70126880',
    high: '7.18687000',
    high_timestamp: '2018-01-05T00:00:00.000Z',
    market_cap: '58767727.57',
    max_supply: '100000000',
    price: '0.83802000',
    price_date: '2019-04-08',
    currency: 'ETP',
    rank: '96'
  },
  {
    circulating_supply: '350000000',
    high: '2.83125000',
    high_timestamp: '2018-01-10T00:00:00.000Z',
    market_cap: '54558000.00',
    max_supply: null,
    price: '0.15588000',
    price_date: '2019-04-08',
    currency: 'QASH',
    rank: '97'
  }
];

const currencies = response.map(({ currency }) => currency);
console.log(currencies);

ES5 语法:

var response = [{
    circulating_supply: '70126880',
    high: '7.18687000',
    high_timestamp: '2018-01-05T00:00:00.000Z',
    market_cap: '58767727.57',
    max_supply: '100000000',
    price: '0.83802000',
    price_date: '2019-04-08',
    currency: 'ETP',
    rank: '96'
  },
  {
    circulating_supply: '350000000',
    high: '2.83125000',
    high_timestamp: '2018-01-10T00:00:00.000Z',
    market_cap: '54558000.00',
    max_supply: null,
    price: '0.15588000',
    price_date: '2019-04-08',
    currency: 'QASH',
    rank: '97'
  }
];

var currencies = response.map(function(item) {
  return item.currency;
});
console.log(currencies);