用例 1：对数字求和
const numbers= [1, 2, 3, 4, 5];
const sum = numbers.reduce((acc, curr) => acc + curr, 0);
console.log(sum); // Output: 15
用例2：对对象进行分组
const people = [
{ name: 'Alice', age: 25 },
{ name: 'Bob', age: 30 },
{ name: 'Charlie', age: 25 },
{ name: 'Dave', age: 30 }
];
const groupByAge = people.reduce((acc, curr) => {
if (!acc[curr.age]) {
acc[curr.age] = [];
}
acc[curr.age].push(curr);
return acc;
}, {});
console.log(groupedByAge);
/*
Output:
{
'25': [{ name: 'Alice', age: 25 }, { name: 'Charlie', age: 25 }],
'30': [{ name: 'Bob', age: 30 }, { name: 'Dave', age: 30 }]
}
*/
用例3：创建查找映射
const products = [
{ id: 1, name: 'Laptop', price: 999 },
{ id: 2, name: 'Phone', price: 699 },
{ id: 3, name: 'Tablet', price: 499 },
];
const productMap = products.reduce((acc, curr) => {
acc[curr.id] = curr;
return acc;
}, {});
console.log(productMap);
/*
Output:
{
'1': { id: 1, name: 'Laptop', price: 999 },
'2': { id: 2, name: 'Phone', price: 699 },
'3': { id: 3, name: 'Tablet', price: 499 }
}
*/
用例4：展平数组
const nestedArray = [[1, 2], [3, 4], [5, 6]];
const flattenedArray = nestedArray.reduce((acc, curr) => acc.concat(curr), []);
console.log(flattenedArray); // Output: [1, 2, 3, 4, 5, 6]
