如何使用 ES6 将 javascript map 解析为数组

Question

I need to parse a JS map, converting it into an array, with the following form:

[
  {
    name: "21 years old",
    totalUsers: 2,
  },
  ...
]

So, if for example I have this map:

const ages = {
  "21": 2,
  "18": 10,
}

The method "parseAges" has to return:

[
  {
    name: "21 years old",
    totalUsers: 2,
  },
  {
    name: "18 years old",
    totalUsers: 10,
  },
]

This is the way I am doing it using for...of (ES2017):

const ages = {
  "21": 2,
  "18": 10,
}

function parseAges() {
  const agesArr = [];

  for (const [key, value] of Object.entries(ages)) {
    agesArr.push({
      name: `${key} years old`,
      totalUsers: value
    })
  }

  return agesArr;
}

console.log(parseAges());

How can I do it without the for...of, in ES6?

Answer 1

This is the way I am doing it using for...of (ES2017):

for/of is part of ES6 ( ES2015 ).

How can I do it without the for...of, in ES6?

There was no particular syntax added in ES6, other than for/of, that would make this easier than using a newer or older syntax.

Object.entries is one alternative ( ES2017 ):

const list = Object.entries(ages).map(([age, users]) => ({
  name: `${age} years old`,
  totalUsers: users,
}));

Object.keys is another alternative (ES5/ ES2009 ):

const list = Object.keys(ages).map((age) => ({
  name: `${age} years old`,
  totalUsers: ages[age],
}));