在ES6中平展对象数组

Question

给定这样的对象的javascript数组：

[ { type: 'type1',
    target: 'target1',
    intent: 'intent1',
    pattern: 'pattern1' },
  { type: 'type1',
    target: 'target2',
    intent: 'intent1',
    pattern: 'pattern2' },
  { type: 'type2',
    target: 'target1',
    intent: 'intent2',
    pattern: 'pattern3' } ]

如何使用ES6创建这样的对象？

[{
   uniqueKey: 'intent1',     
   patterns: [{
     type: 'type1',
     target: 'target1',
     pattern: 'pattern1'
   }, {
     type: 'type1',
     target: 'target2',
     pattern: 'pattern2'
   }]
}, {
   uniqueKey: 'intent2',      
   patterns: [{
     type: 'type2',
     target: 'target1',
     pattern: 'pattern3'
   }]
}]

我已经看到了很多带有reduce ， map ， filter ， set ， [...arr]的示例，但是我一直在努力地将它们简洁地结合在一起。

Answer 1

这样的事情行吗？ 它可能不是最有效的，但是我认为它会在给定示例数据集的情况下满足您的需求。

const collection = [ 
  { type: 'type1',
    target: 'target1',
    intent: 'intent1',
    pattern: 'pattern1' 
  },
  { type: 'type1',
    target: 'target2',
    intent: 'intent1',
    pattern: 'pattern2' 
  },
  { type: 'type2',
    target: 'target1',
    intent: 'intent2',
    pattern: 'pattern3' 
  }
];

// Iterate through your collection, building on arr which 
// starts out as an empty array when certain conditions are met.
const result = collection.reduce((arr, item) => {

  const key = item.intent;
  const pattern = {
    type: item.type,
    target: item.target,
    pattern: item.pattern
  };

  // Check if an there's an existing entry with the current key
  if (arr.length > 0 && arr.some(entry => entry.uniqueKey === key)) {
    // If so, push the current pattern object into the existing entry's
    // patterns key.
    const existingEntry = arr.findIndex(entry => entry.uniqueKey === key);
    arr[existingEntry].patterns.push(pattern)

  // If there's no existing entry with the current key
  } else {
    // Create a new entry with the current key and pattern
    const formattedEntry = {
      uniqueKey: key,
      patterns: [pattern]
    }
    arr.push(formattedEntry);
  }
  return arr
}, []);

console.log('result', result);

// output - returns an array with two objects, the first with a patterns array
// containing two objects matching the uniqueKey: intent1. The other
// with a patterns array containing one object matching uniqueKey: intent2.
// [{
//    patterns: [
//      {
//        type: 'type1',
//        target: 'target1',
//        pattern: 'pattern1'
//      }, 
//      {
//        type: 'type1',
//        target: 'target2',
//        pattern: 'pattern2'
//      }
//    ],
//    uniqueKey: 'intent1',     
//  }, 
//  {  
//    patterns: [{
//      pattern: 'pattern3'
//      target: 'target1',
//      type: 'type2',
//    }]
//    uniqueKey: 'intent2',  
// }]