编写一个函数来对对象数组进行排序（通过使用另一个对象来指定排序路径和顺序）

Question

我将编写一个函数，通过使用另一个对象作为其参数来确定根据哪种结构执行排序，从而以某种结构（仅知道它是对象数组，例如产品列表）对任何JSON进行排序键。

// The json that I get might looks like something like this.
// I just write one item of the array, but all of them are the same.
// But the blueprint of the items in each json are different.
const dataArray = [
  {
    id: 100,
    name: 'product_1',
    price: 99.95,
    color: ['#fff', '#f0f', '#00f'],
    category: ['cat_1', 'cat_2'],
    booleanKey: true,
    foo: {
      foo1: 12,
      foo2: 'string value',
      foo3: {
        foo3_1: 'string value',
        foo3_2: 732.342
      },
      foo4: [
        {
          foo4_1_1: 853,
          foo4_1_2: 24,
        },
        {
          foo4_2_1: 'string value',
          foo4_2_2: 435,
          foo4_2_3: 25.35,
        }
      ]
    },
    bar: {
      bar1: {
        bar1_1: 313,
        bar1_2: 32.73
      },
      bar2: 75.3
    }
  }
];

// The function to sort the array
const sortData = obj => {
  return dataArray.sort((a, b) => {
    // Do something to return the correct value
  });
}

// Sort array ascending by value 1, and descending by value -1
const result = sortData({foo: {foo3: {foo3_2: 1}}});
const anotherResult = sortData({bar: {bar2: -1}});
const anotherResult = sortData({price: 1});

因为我必须编写一个函数来对具有任何结构的任何项目进行排序，所以我必须使用它们传递给我的obj作为基于该对象的键对数组进行排序的参数。

我找到了这种解决方案，依此类推：

// The sample array that be used from the other answer
const fooArray = [
  { foo1: { foo2: { foo3: 123 } } },
  { foo1: { foo2: { foo3: 987 } } },
  { foo1: { foo2: { foo3: 456 } } },
  { foo1: { foo2: { foo3: 789 } } },
  { foo1: { foo2: { foo3: 321 } } },
  { foo1: { foo2: { foo3: 654 } } }
];
const sortData = obj => {
  const pathArray = [];
  while(typeof(obj) == 'object') {
    pathArray.push(Object.keys(obj)[0]);
    obj = obj[pathArray[pathArray.length - 1]];
  }
  const order = obj;
  return fooArray.sort((a, b) => {
    for(let pathKey of pathArray) {
      a = a[pathKey];
      b = b[pathKey];
    }
    return (a - b) * order;
  });
}
const foo = sortData({ foo1: { foo2: { foo3: 1 } } });

还有其他建议或想法吗？

Answer 1

对于排序逻辑，这非常简单：

const sortData = path => {
  const sortOrder = query(path, path)

  return dataArray.sort((a, b) => {
    const valueOfA = query(a, path)
    const valueOfB = query(b, path)

    if (valueOfA < valueOfB) return -sortOrder
    if (valueOfA > valueOfB) return sortOrder
    return 0
  })
}

这里唯一复杂的事情是如何从对象类型的另一个参数中查询排序路径和顺序。

所以我在这里定义了一个辅助函数来完成这项工作：

function query (target, path) {
  const [key] = Object.keys(path)

  if (typeof path[key] !== 'object') {
    return target[key]
  }

  return query(path[key], target)
}

您可以在这里进行测试：

let dataArray = [{id: 100}, {id: 200}]

const sortData = path => {
  const sortOrder = query(path, path)

  return dataArray.sort((a, b) => {
    const valueOfA = query(a, path)
    const valueOfB = query(b, path)

    if (valueOfA < valueOfB) return -sortOrder
    if (valueOfA > valueOfB) return sortOrder
    return 0
  })
}

console.log(sortData({id: 1}))        // 100, 200
console.log(sortData({id: -1}))       // 200, 100

dataArray = [
  {foo: {bar: 'bar'}, a:'a', b:'b'},
  {foo: {bar: 'car'}, a:'A', b:'B'}
]

console.log(sortData({foo: {bar: 1}}))     // [...bar, ...car]
console.log(sortData({foo: {bar: -1}}))    // [...car, ...bar]

function query (target, path) {
  const [key] = Object.keys(path)

  if (typeof path[key] !== 'object') {
    return target[key]
  }

  return query(path[key], target)
}

Answer 2

使用Sort array of objects by string property value作为按任意选择的字符串或对象编号进行排序的参考实现，我们只需要使用下面的criteria()函数来实现从对象到选择器的转换：

const criteria = (o, select = v => v) => {
  const [[key, order]] = Object.entries(o)
  const fn = v => select(v)[key]
  return typeof order === 'object'
    ? criteria(order, fn)
    : { order, fn }
}

const sortData = o => (({ order, fn }) =>
  (a, b) => {
    const fa = fn(a)
    const fb = fn(b)
    return order * (-(fa < fb) || +(fa > fb))
  }
)(criteria(o))

const foo = sortData({ foo1: { foo2: { foo3: 1 } } })
const fooArray = [
  { foo1: { foo2: { foo3: 123 } } },
  { foo1: { foo2: { foo3: 987 } } },
  { foo1: { foo2: { foo3: 456 } } },
  { foo1: { foo2: { foo3: 789 } } },
  { foo1: { foo2: { foo3: 321 } } },
  { foo1: { foo2: { foo3: 654 } } }
]

console.log(fooArray.sort(foo))

const bar = sortData({ bar1: { bar2: { bar3: -1 } } })
const barArray = [
  { bar1: { bar2: { bar3: 'abc' } } },
  { bar1: { bar2: { bar3: 'ihg' } } },
  { bar1: { bar2: { bar3: 'def' } } },
  { bar1: { bar2: { bar3: 'ghi' } } },
  { bar1: { bar2: { bar3: 'cba' } } },
  { bar1: { bar2: { bar3: 'fed' } } }
]

console.log(barArray.sort(bar))

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