可以通过使用类型断言（type assertion）来解决此问题，即告诉编译器我们知道表达式的实际类型。示例代码如下：

interface Item { id: number; name: string; layoutType: string; }

const items: Item[] = [ { id: 1, name: 'Item 1', layoutType: 'grid' }, { id: 2, name: 'Item 2', layoutType: 'list' }, { id: 3, name: 'Item 3', layoutType: 'grid' }, { id: 4, name: 'Item 4', layoutType: 'list' }, ];

function getItemsByLayoutType(layoutType: string) { const filteredItems = items.filter((item) => item.layoutType === layoutType); return filteredItems.map((item) => { if (item.layoutType === 'grid') { return { ...item, grid: true } as { id: number, name: string, layoutType: string, grid: true }; // 使用类型断言 as { id: number, name: string, layoutType: string, grid: true } 告诉编译器实际类型 } else { return { ...item, list: true } as { id: number, name: string, layoutType: string, list: true }; // 同样使用类型断言 } }); }

console.log(getItemsByLayoutType('grid')); // 输出： [{ id: 1, name: 'Item 1', layoutType: 'grid', grid: true }, { id: 3, name: 'Item 3', layoutType: 'grid', grid: true }]