TypeScript版本： 2.7.1-insiders.20180127
搜索词： array destructuring rest assignment
代码：
// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.
const [stringA, ...numbers] = ['string', 1, 2];
// const [stringA, ...numbers] = <[string, number, number]>['string', 1, 2];
// const [stringA, ...numbers]: [string, number[]] = ['string', 1, 2];
// const [stringA, ...numbers]: [string, [number, number]] = ['string', 1, 2];预期行为： 期望 numbers 的类型为 number[],而不是 (string | number)[]。TS也不允许将其标记为元组。
实际行为： const numbers: (string | number)[]
**Playground链接：**http://www.typescriptlang.org/play/index.html#src=const%20%5BstringA%2C%20...numbers%5D%20%3D%20%5B'string'%2C%201%2C%202%5D%3B%0A%2F%2F%20const%20%5BstringA%2C%20...numbers%5D%20%3D%20%3C%5Bstring%2C%20number%2C%20number%5D%3E%5B'string'%2C%201%2C%202%5D%3B%0A%2F%2F%20const%20%5BstringA%2C%20...numbers%5D%3A%20%5Bstring%2C%20number%5B%5D%5D%20%3D%20%5B'string'%2C%201%2C%202%5D%3B%0A%2F%2F%20const%20%5BstringA%2C%20...numbers%5D%3A%20%5Bstring%2C%20%5Bnumber%2C%20number%5D%5D%20%3D%20%5B'string'%2C%201%2C%202%5D%;
相关问题：
5条答案
按热度按时间xpszyzbs1#
正确的类型应该是
const [stringA, ...numbers]: [string, number, number],而numbers应该被正确推断。这是一个我们应该修复的bug。w1jd8yoj2#
我也曾遇到过这个关于重载函数的问题。
$x_1a^0b^1x$
o4hqfura3#
在开放帖子中的问题已在
typescript@next中修复，甚至可能在3.0.0-rc中修复。numbers现在类型为number[]。yvfmudvl4#
重复：#3369。在没有显式类型注解的情况下，元组类型不会被推断。你可以在#16656中找到相关讨论。
ahy6op9u5#
元组类型在没有显式类型注解的情况下不会被推断
@mhegazy 那么如何将
numbers的剩余赋值注解为元组？我相信我在最后一行尝试过这个：