如何在javascript中如下拼出数组

Question

如何创建像[['India', 6],['USA', 3]]

这样的数组

使用以下数据

     [
{ _id: 'India', count: 6 },
  { _id: 'USA', count: 3 }
   ]

Answer 1

您可以使用Array#map

执行此操作

var d = [{
    _id: 'India',
    count: 6
  },
  {
    _id: 'USA',
    count: 3
  }
];

var output = d.map(function(ele) {
  return [ele._id, ele.count]
});

console.log(output);

如果您对使用ES6的解决方案持开放态度，使用destructuring和arrow functions

会更清晰

let d = [{
    _id: 'India',
    count: 6
  },
  {
    _id: 'USA',
    count: 3
  }
];

// Destructure every array element into { _id, count }
// Pass an expression in the RHS that just creates an array using _id and count
let output = d.map(({ _id, count }) => [_id, count])

console.log(output);