lodash 中的对象逆变器不会丢失密钥

Question

尝试使用_.invertlodash 处理对象，将旧密钥收集到数组中，而不是丢失它们。

这是我成功做到这一点的方法：

let tokens = {
    y: 'years',
    Y: 'years',
    M: 'months',
    mo: 'months',
    Mo: 'months',
    w: 'weeks',
    W: 'weeks',
    d: 'days',
    D: 'days',
    h: 'hours',
    H: 'hours',
    m: 'minutes',
    mi: 'minutes',
    Mi: 'minutes',
    s: 'seconds',
    S: 'ms'
  },
  print = JSON.stringify(inverter(tokens), null, 2);

document.querySelector('#test').innerHTML = print;

function inverter(obj) {
  let out = {};
  _.forOwn(obj, (o, k) => {
    out[o] = _.concat(out[o] || [], [k]);
  });
  return out;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js"></script>

<pre id="test"></pre>

大多数时候，我觉得我对 lib 的使用就像游泳锤一样优雅，所以我的问题是：是否有比我当前功能更简单、更优雅的“lodashy”方式？inverter()

Answer 1

使用_.invertBy()。根据文档：

每个倒排键对应的倒排值是负责生成倒排值的键数组。

const tokens = {"y":"years","Y":"years","M":"months","mo":"months","Mo":"months","w":"weeks","W":"weeks","d":"days","D":"days","h":"hours","H":"hours","m":"minutes","mi":"minutes","Mi":"minutes","s":"seconds","S":"ms"};
  
const result = _.invertBy(tokens);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js"></script>

<pre id="test"></pre>