假设我们有一个对象数组,其中包含有关某些汽车的信息,例如:
const arr = [ { "group":[], "name": "All Makes", "code": "" }, { "group":["Group A"], "name": "BMW", "code": "X821" }, { "group":["Group B"], "name": "Audi", "code": "B216" }, { "group":["Group B"], "name": "Ford", "code": "P385" }, { "group":["Group B", "Group C"], "name": "Mercedes", "code": "H801" }, { "group":["Group C"], "name": "Honda", "code": "C213" } ];
我们需要编写一个JavaScript函数,该函数接受一个这样的对象数组。该函数应基于每个对象的group属性对该数组的对象进行分组。如果group属性包含多个元素,则该对象应出现在两个组中。
因此。],对于上述数组,输出应类似于-
const output = [ { "group": "Group A", "cars": [ { name: "BMW", code: "X821" } ] }, { "group": "Group B", "cars": [ { name: "Audi", code: "B216" }, { name: "Ford", code: "P385" }, { name: "Mercedes", code: "H801" } ] }, { "group": "Group C", "cars": [ { name: "Mercedes", code: "H801" }, { name: "Honda", code: "C213" } ] } ];
为此的代码将是-
const arr = [ { "group":[], "name": "All Makes", "code": "" }, { "group":["Group A"], "name": "BMW", "code": "X821" }, { "group":["Group B"], "name": "Audi", "code": "B216" }, { "group":["Group B"], "name": "Ford", "code": "P385" }, { "group":["Group B", "Group C"], "name": "Mercedes", "code": "H801" }, { "group":["Group C"], "name": "Honda", "code": "C213" } ]; const groupTogether = (arr = []) => { let res = [] res = Object.entries(arr.reduce((acc, { group, ...r }) => { group.forEach(key => acc[key] = (acc[key] || []).concat({...r})); return acc; }, {})) return res.map(([group, arr]) => ({ group, arr })); }; console.log(JSON.stringify(groupTogether(arr), undefined, 4));
输出结果
控制台中的输出将是-
[ { "group": "Group A", "arr": [ { "name": "BMW", "code": "X821" } ] }, { "group": "Group B", "arr": [ { "name": "Audi", "code": "B216" }, { "name": "Ford", "code": "P385" }, { "name": "Mercedes", "code": "H801" } ] }, { "group": "Group C", "arr": [ { "name": "Mercedes", "code": "H801" }, { "name": "Honda", "code": "C213" } ] } ]