javascript - 减少javascript中的对象数组

Question

我在 javascript 中有一个对象数组，我想减少它们。请参阅下面的代码。6 位数或更多数字的消息已验证，更少未验证。我将它们分组。

const myArray = [
  { group: 'groupA', message: 'Text without a number', sl: '1A' },
  { group: 'groupA', message: 'Text with a number WO5467829', sl: '1A' },
  { group: 'groupB', message: 'Text without a number', sl: '1A' },
  { group: 'groupA', message: 'Text with a number WO5467829', sl: '1A' },
  { group: 'groupB', message: 'Text with a number WO5467829', sl: '1A' },
  { group: 'groupC', message: 'Text without a number', sl: '1B' },
  { group: 'groupD', message: 'Text with a number Tick0127866', sl: '1B' },
  { group: 'groupC', message: 'Text without a number', sl: '1A' }
];

output = myArray.reduce((acc, line) => {
  let yes = 0;
  let no = 0;

  line.message.match(/\d{6,}/) ? yes++ : no++;

  acc[line.group] = acc[line.group] || {};
  acc[line.group].verified = (acc[line.group].verified || 0) + yes;
  acc[line.group].unverified = (acc[line.group].unverified || 0) + no;
  return acc;
}, {});

console.log('output', output);

但是我希望输出也是一个对象数组，如下所示:

[
  { group: 'groupA', verified: 2, unverified: 1 },
  { group: 'groupB', verified: 1, unverified: 1 },
  { group: 'groupC', verified: 0, unverified: 2 },
  { group: 'groupD', verified: 1, unverified: 0 }
]

我该怎么做？

Answer 1

使用数组作为累加器的初始值，在 .reduce 中，使用 findIndex 检查当前组，如果找到，更新 verified 和 未验证 值，否则，插入一个新值:

const myArray = [
  { group: "groupA", message: "Text without a number", sl: "1A" },
  { group: "groupA", message: "Text with a number WO5467829", sl: "1A" },
  { group: "groupB", message: "Text without a number", sl: "1A" },
  { group: "groupA", message: "Text with a number WO5467829", sl: "1A" },
  { group: "groupB", message: "Text with a number WO5467829", sl: "1A" },
  { group: "groupC", message: "Text without a number", sl: "1B" },
  { group: "groupD", message: "Text with a number Tick0127866", sl: "1B" },
  { group: "groupC", message: "Text without a number", sl: "1A" }
];

output = myArray.reduce((acc, line) => {
  let yes = 0;
  let no = 0;

  line.message.match(/\d{6,}/) ? yes++ : no++;

  // check if you have the group in the accumulator
  const ndx = acc.findIndex(e => e.group === line.group);

  // if you have it, manipulate verified and unverified
  if (ndx > -1) {
    acc[ndx].verified = (acc[ndx].verified || 0) + yes;
    acc[ndx].unverified = (acc[ndx].unverified || 0) + no;
  } else {
    // insert a new entry instead
    acc.push({
      group: line.group,
      verified: yes,
      unverified: no
    });
  }

  return acc;
}, []); // use an array as the initial value of the accumulator

console.log(output);