Array.filter() 和过滤对象的引用

Question

如果我们在一个对象数组上应用array.filter函数，结果数组是否包含对它从第一个数组过滤的对象的引用？

Answer 1

does the resultant array hold reference to the objects it filtered from the first array

Yes, they're the same objects, filter doesn't clone them. It's just like doing this doesn't clone an object:

const a = {id: 1, value: "one"};
const b = a;
a.value = a.value.toUpperCase();
console.log(b.value); // "ONE" <== In caps

Live Example with filter :

 const a = [ {id: 1, value: "one"}, {id: 2, value: "two"}, {id: 3, value: "three"} ]; const b = a.filter(entry => entry.id % 2); a[0].value = a[0].value.toUpperCase(); console.log(a); console.log(b);

 .as-console-wrapper { max-height: 100% !important; }

Note that "ONE" is in all caps in the object, regardless of which array you get the object reference from.

Answer 2

just an example that it does, check @TJ Crowder's answer links

 const arr = [{a:1}, {a:2}, {a:2}]; const newArr = arr.filter(v => va < 3); newArr[0].a = 5; console.log(arr); console.log(newArr);