typescript 如何把字面量数组转为联合类型声明?

如果这个字面量数组没有指定类型的话是可以的：

const routes = [
  { path: '/test' }
] as const

type paths = typeof routes[number]['path']

但是如果routes指定了类型（为了书写的时候有语法提示），就不行，paths会推断成string类型：

const routes: RouteRecordRaw[] = [
  { path: '/test' }
] as const

type paths = typeof routes[number]['path']

有什么解决方法吗

解决方法

import type { RouteRecordRaw } from 'vue-router'

type Route<T> = Omit<RouteRecordRaw, 'path'> & { path: T }

function defineRoutes<T extends string>(routes: Route<T>[]) {
  return routes
}

const routes = defineRoutes([
  {
    path: '/contract/index'
  }
])

type paths = typeof routes[number]['path']