javascript - json如何将行转换为列

Question

我有一个数组 json 对象，想要将行转换为列，并将旁边的列作为列的值。就像postgresql的函数crosstab

json是这样的:

{"marketcode":"01","size":"8,5","amount":1},
{"marketcode":"01","size":"9","amount":1},
{"marketcode":"01","size":"10","amount":0},

我希望它是这样的:

{"marketcode": "01", "8,5": 1, "9": 1, "10": 0}

我搜索了 lodash，但没有找到任何内容

Answer 1

希望这是您正在寻找的:

const convert = toConvert => {
    const map = toConvert.reduce((r, {marketcode, size, amount}) => {
    if (r.has(marketcode))
        r.set(marketcode, {...r.get(marketcode), [size]: amount});
     else
        r.set(marketcode, {marketcode, [size]: amount});
    return r;
  }, new Map());
  return [...map.values()];
};

fiddle :https://jsfiddle.net/cccheng118/pyh2L85k/6/