你可以延长
toUpperCase
interface String {
toUpperCase(this: 'hour'|'day'|'week'|'month') : 'HOUR'|'DAY'|'WEEK'|'MONTH'
}
declare let low: 'hour'|'day'|'week'|'month';
let up = low.toUpperCase(); // typed as "HOUR" | "DAY" | "WEEK" | "MONTH"
如果您在模块中,则需要在全局命名空间中重新声明字符串:
declare global {
interface String {
toUpperCase(this: 'hour' | 'day' | 'week' | 'month'): 'HOUR' | 'DAY' | 'WEEK' | 'MONTH'
}
}