Question

我有一个对象数组。每个对象内都有另一个数组。我想从这些数组中提取不同的值。

var data = [
            {categorie: 'Stuff', type: 'One', designs: ['A', 'B']},
            {categorie: 'Stuff', type: 'Two', designs: ['C']},
            {categorie: 'Stuff', type: 'One', designs: ['D']},
            {categorie: 'Other', type: 'Three', designs: ['C', 'D']}
        ];
console.log([...new Set(data.map(x => x.categorie))]);
console.log([...new Set(data.map(x => x.type))]);

//expected output for designs ['A','B','C','D']

Answer 1

您可以使用flatMap()代替map()

var data = [
            {categorie: 'Stuff', type: 'One', designs: ['A', 'B']},
            {categorie: 'Stuff', type: 'Two', designs: ['C']},
            {categorie: 'Stuff', type: 'One', designs: ['D']},
            {categorie: 'Other', type: 'Three', designs: ['C', 'D']}
        ];

console.log([...new Set(data.flatMap(x => x.designs))]);

//expected output for designs ['A','B','C','D']

如果您的浏览器不支持flatMap()，则可以将concat()与扩展运算符一起使用。

var data = [
            {categorie: 'Stuff', type: 'One', designs: ['A', 'B']},
            {categorie: 'Stuff', type: 'Two', designs: ['C']},
            {categorie: 'Stuff', type: 'One', designs: ['D']},
            {categorie: 'Other', type: 'Three', designs: ['C', 'D']}
        ];

console.log([...new Set([].concat(...data.map(x => x.designs)))]);

//expected output for designs ['A','B','C','D']

Answer 2

您还需要从设计中挑选一套。

var data = [{ categorie: 'Stuff', type: 'One', designs: ['A', 'B'] }, { categorie: 'Stuff', type: 'Two', designs: ['C'] }, { categorie: 'Stuff', type: 'One', designs: ['D'] }, { categorie: 'Other', type: 'Three', designs: ['C', 'D'] }],
    unique = data.reduce((s, { designs }) => [...new Set([...s, ...designs])], []);

console.log(unique);

Answer 3

一个简单的解决方案是：

var data = [
            {categorie: 'Stuff', type: 'One', designs: ['A', 'B']},
            {categorie: 'Stuff', type: 'Two', designs: ['C']},
            {categorie: 'Stuff', type: 'One', designs: ['D']},
            {categorie: 'Other', type: 'Three', designs: ['C', 'D']}
        ];

var uniqueLetters = []

data.forEach(obj => {
  obj.designs.forEach(letter => {
    if (uniqueLetters.indexOf(letter) < 0) {
      uniqueLetters.push(letter)
    }
  })
})

console.log(uniqueLetters)

Answer 4

尝试一下。纯JavaScript解决方案。

var output = [];
for(var i=0; i<data.length; i++){
for(var j=0; j<data[i].designs.length; j++ ){
  if(output.indexOf(data[i].designs[j]) === -1) {
  output.push(data[i].designs[j])
  }
}
}
console.log(output)
//expected output for designs ['A','B','C','D']

对象数组中Array中不同的值

4 个答案: