node.js - 为什么从定制模块导入的函数在 JSfiddle 中工作时表现不同？

Question

我有 2 个文件 index.js 和 sort.js。

index.js 文件包含一个变量“x”，其值为英文单词对象数组。每个对象都包含一个“pos”属性，该属性又是一个数组，其值可以是 n、v、adj、adv(至少包含一个值)

sort.js 包含一个以变量“x”作为参数的函数。然后它以这样的方式排列单词，使每个 pos 值成为主数组内的一个单独的数组。

代码正在 jsfiddle 中运行，但在我的项目中得到一个空数组作为输出。我在 sort.js 文件中尝试了不同的导出方法，例如 module.exports 等。

注意:我使用 lodash 作为依赖项。

这是两个文件的代码:

index.js

const _ = require("lodash");
const { sortByPos } = require("../lib/sort");

/* 
 Some extra code here
*/

let x = [
    {
      word: "music",
      pos: ["n"],
      first: "m",
      wordCount: 1,
      len: 5
    },
    {
      word: "scale",
      pos: ["n", "v"],
      first: "s",
      wordCount: 1,
      len: 5
    },
    {
      word: "beats",
      pos: ["n"],
      first: "b",
      wordCount: 1,
      len: 5
    },
    {
      word: "surmount",
      pos: ["v"],
      first: "s",
      wordCount: 1,
      len: 8
    },
    {
      word: "euphony",
      pos: ["n", "adv"],
      first: "e",
      wordCount: 1,
      len: 7
    },
    {
      word: "trounce",
      pos: ["adj", "v"],
      first: "t",
      wordCount: 1,
      len: 7
    }
  ];

  console.log(sortByPos(x))

排序.js

const _ = require("lodash");
exports.sortByPos = words => {
 return _.reduce(
 words,
 (result, obj) => {
   _.forEach(obj.pos, el => (result[el] || (result[el] = [])).push(obj));
   return result;
 },
 []
 );
};

<小时/>

更新:代码在 JSFiddle 中也无法正常工作。

Answer 1

您的reduce累加器(结果)是一个数组，但您为其分配非数字键。相反，使用对象作为累加器，如果需要数组，请使用 _.values() 或 Object.values() 将其转换为数组:

const sortByPos = words => {
  return _.reduce(
    words,
    (result, obj) => {
      _.forEach(obj.pos, el => (result[el] || (result[el] = [])).push(obj));
      return result;
    }, {}
  );
};

let x = [{"word":"music","pos":["n"],"first":"m","wordCount":1,"len":5},{"word":"scale","pos":["n","v"],"first":"s","wordCount":1,"len":5},{"word":"beats","pos":["n"],"first":"b","wordCount":1,"len":5},{"word":"surmount","pos":["v"],"first":"s","wordCount":1,"len":8},{"word":"euphony","pos":["n","adv"],"first":"e","wordCount":1,"len":7},{"word":"trounce","pos":["adj","v"],"first":"t","wordCount":1,"len":7}];

console.log(sortByPos(x)) // an object of arrays

console.log(_.values(sortByPos(x))) // an array of arrays

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