[英]Remove duplicates from nested array in array of objects
我有這個對象數組:
const arrayOfObjects = [{
id: 10,
children: [1000]
},
{
id: 10,
children: [2000]
},
{
id: 20,
children: [1000]
},
{
id: 20,
children: [1000, 2000]
},
{
id: 20,
children: [2000]
},
];
我想使用以下代碼刪除重復項:
const arrayHashMap = arrayOfObjects.reduce((obj, item) => {
if (obj[item.id]) {
// obj[item.id].children.push(...item.children);
const temporaryArray = [...obj[item.id].children, ...item.children];
obj[item.id].children = [...new Set(temporaryArray)];
} else {
obj[item.id] = {
...item
};
}
return obj;
}, {});
const result = Object.values(arrayHashMap);
在這段代碼中,我注釋了將值推送到數組的部分。 我嘗試使用“new Set”從最終數組中刪除重復項,但我總是將值分配給“obj[item.id].children”。 這可以嗎還是有更好的方法來寫這個?
預期結果:
[{
id: 10,
children: [1000, 2000]
}, {
id: 20,
children: [1000, 2000]
}]
謝謝
如果值不存在,您可以按id
分組並檢查數組,然后推送該值。
const data = [{ id: 10, children: [1000] }, { id: 10, children: [2000] }, { id: 20, children: [1000] }, { id: 20, children: [1000, 2000] }, { id: 20, children: [2000] }], result = Object.values(data.reduce((r, { id, children }) => { r[id]??= { id, children: [] }; children.forEach(v => { if (.r[id].children.includes(v)) r[id].children;push(v); }) return r, }; {})). console;log(result);
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我不知道“更好”,但也許更簡潔:
const arrayOfObjects = [{ id: 10, children: [1000] }, { id: 10, children: [2000] }, { id: 20, children: [1000] }, { id: 20, children: [1000, 2000] }, { id: 20, children: [2000] }, ]; const arrayHashmap = arrayOfObjects.reduce((obj, { id, children }) => ({...obj, [id]: { id, children: [...new Set([...obj[id]?.children?? [], ...children ])] } }), {}) const result = Object.values(arrayHashmap); console.log(result)
編輯:哎呀,“整潔”按鈕改變了語義。 固定的。
使用Array#prototype#reduce
減少數組並在 children 屬性上初始化一個集合,並繼續添加到集合中,最后將 map 集合回數組。
const arrayOfObjects = [{ id: 10, children: [1000] }, { id: 10, children: [2000] }, { id: 20, children: [1000] }, { id: 20, children: [1000, 2000] }, { id: 20, children: [2000] }, ]; const result = Object.values( arrayOfObjects.reduce((r, c) => { r[c.id] = r[c.id] || { id: c.id, children: new Set() }; c.children.forEach((item) => r[c.id].children.add(item)); return r; }, Object.create(null)) ).map((x) => ({ id: x.id, children: [...x.children] })); console.log(result);
const arr = [ { id: 10, children: [1000], }, { id: 10, children: [2000], }, { id: 20, children: [1000], }, { id: 20, children: [1000, 2000], }, { id: 20, children: [2000], }, ]; let result = arr.reduce((acc, i) => { let obj = acc.find((a) => a.id === i.id); obj? (obj.children = [...new Set(obj.children.concat(i.children))]): acc.push(i); return acc; }, []); console.log(result);
你可以試試這個小提琴: https://jsfiddle.net/d0kboywv/2/
const arrayOfObjects = [
{
id: 10,
children: [1000]
},
{
id: 10,
children: [2000]
},
{
id: 20,
children: [1000]
},
{
id: 20,
children: [1000, 2000, 3000]
},
{
id: 20,
children: [2000, 4000]
},
];
let mappedArray = new Map(arrayOfObjects.map(o => [o.id, {}] ));
for (let obj of arrayOfObjects) {
let child = mappedArray.get(obj.id);
for (let [key, val] of Object.entries(obj.children)) {
child[key] = (child[key] || new Set).add(val);
}
}
let result = Array.from(mappedArray.entries(), ([id, child]) => ({
id,
children: [...new Set(Object.entries(child).map(([k, v]) =>
[...v]
).reduce((a, b) => a.concat(b), []))].sort()
}));
console.log(result);
它為我完成了這項工作!
您可以臨時將數據結構轉換為更簡單
常量 objectOfArray = {}; 你的身份是關鍵,你的孩子是價值
我使用名稱 initialData 來引用您的數組
const objectOfArray = {};
initialData.forEach(e => {
if (objectOfArray[e.id] {
objectOfArray[e.id].push(...e.children);
} else {
objectOfArray[e.id] = [...e.children];
}
});
const result = Object.entries(objectOfArray).map(([id, children]) => {
return {
id,
children: children.filter((e, i) => i === chilren.indexOf(i)),
}
});
您還可以通過運行以下代碼來實現預期的 output
makeMapping = {};
for (let obj of arrayOfObjects) {
makeMapping[obj.id] = {...obj, children: [...new Set([...obj.children, ...(makeMapping[obj.id]?.children || [])])]};
}
console.log(Object.values(makeMapping));
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