[英]Map an array into array of objects with given object at the top of resulting array
假設你有一個數組和一個看起來像這樣的對象
const arr = ["a", "b", "c"]
const obj = {tree : -1, area: null}
您將如何遍歷所述數組以返回這樣的對象數組,同時將初始值設置為上面的對象。
假設在這種情況下不能使用flatlist()
。
期望輸出: [{tree : -1, area: null}, {tree : 0, area: "a" },{tree : 1, area: "b" },{tree : 2, area: "c" } ]
這個怎么樣:
const arr = ["a", "b", "c"], obj = {tree : -1, area: null}, result = [obj, ...arr.map((area,tree) => ({area,tree}))] console.log(result)
另一方面,您可以將Array.prototype.reduce()
與源對象一起用作初始結果數組值:
const arr = ["a", "b", "c"], obj = {tree : -1, area: null}, result = arr.reduce((r,area,tree) => (r.push({area,tree}),r), [obj]) console.log(result)
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在開頭添加一個元素並使用 map
const arr = ["a", "b", "c"]; const results = [null, ...arr].map((area, i) => ({ tree: i - 1, area })); console.log(results);
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