牛魔王的故事
2023-06-09 17:40:56
我有一個(gè)結(jié)構(gòu)如下的對象?const data = [? ? { academicYearId: 1, classLevelId: 1, subjectId: 1, ...},? ? { academicYearId: 1, classLevelId: 1, subjectId: 2, ...},? ? { academicYearId: 1, classLevelId: 1, subjectId: 3, ...},? ? ,,,?]我需要?jiǎng)?chuàng)建一個(gè)將返回唯一列的函數(shù),例如? ?const uniqueColumns = ( val, columns)=> {? ? ?//? ?}? ?const val = [? ? { id: 1, name: 'n1', val: 1 },? ? { id: 1, name: 'n1', val: 2 },? ? { id: 2, name: 'n2', val: 1 },? ? { id: 3, name: 'n2', val: 2 }? ?]? ?let result = uniqueColumns(val)? ?console.log(val)? ?/**?? ? * Expected? ? * [{ id: 1, name: 'n1'}, { id: 2, name: 'n2'}, { id: 3, name: 'n2'}]? ? */}我試圖查看如何從 JavaScript 中的對象數(shù)組中獲取不同的值?我已經(jīng)設(shè)法想出了下面的? ?const uniqueColumns = (val, columns) =>?? ? ?([...new Set(? ? ? ?val.map(item =>?? ? ? ? ?columns.reduce((prev, next) =>?? ? ? ? ? ?({[next]: item[next], ...prev}), {})? ? ? ?).map(item => JSON.stringify(item)))? ? ?].map(item => JSON.parse(item)))? ?? ?const val = [? ? { id: 1, name: 'n1', val: 1 },? ? { id: 1, name: 'n1', val: 2 },? ? { id: 2, name: 'n2', val: 1 },? ? { id: 3, name: 'n2', val: 2 }? ?]? ?const result = uniqueColumns(val, ['id', 'name'])? ?console.log(result)我想問的是是否有更好的方法而不是必須將對象轉(zhuǎn)換為字符串然后再轉(zhuǎn)換回對象來實(shí)現(xiàn)這一點(diǎn)
1 回答

慕雪6442864
TA貢獻(xiàn)1812條經(jīng)驗(yàn) 獲得超5個(gè)贊
您可以使用數(shù)組 reduce 方法。
const val = [
{ id: 1, name: "n1", val: 1 },
{ id: 1, name: "n1", val: 2 },
{ id: 2, name: "n2", val: 1 },
{ id: 3, name: "n2", val: 2 },
];
const uniqueColumns = (val, columns) => {
let ret = val.reduce((p, c) => {
let obj = {};
columns.forEach((x) => (obj[x] = c[x]));
let key = Object.values(obj);
if (!p[key]) p[key] = obj;
return p;
}, {});
return Object.values(ret);
};
const result = uniqueColumns(val, ["id", "name"]);
console.log(result);
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