对象数组中Array中不同的值

Question

香港专业教育学院有一系列的对象。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concat()与传播运算符一起使用。

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']