84 lines
2.1 KiB
TypeScript
84 lines
2.1 KiB
TypeScript
class C { private p: string };
|
|
|
|
var str: string;
|
|
var bool: boolean;
|
|
var num: number;
|
|
var strOrNum: string | number;
|
|
var strOrBool: string | boolean;
|
|
var numOrBool: number | boolean
|
|
var strOrNumOrBool: string | number | boolean;
|
|
var strOrC: string | C;
|
|
var numOrC: number | C;
|
|
var boolOrC: boolean | C;
|
|
var c: C;
|
|
|
|
// A type guard of the form typeof x === s,
|
|
// where s is a string literal with the value 'string', 'number', or 'boolean',
|
|
// - when true, narrows the type of x to the given primitive type, or
|
|
// - when false, removes the primitive type from the type of x.
|
|
if (typeof strOrNum === "number") {
|
|
num = strOrNum; // number
|
|
}
|
|
else {
|
|
str === strOrNum; // string
|
|
}
|
|
if (typeof numOrBool === "number") {
|
|
num = numOrBool; // number
|
|
}
|
|
else {
|
|
var x: number | boolean = numOrBool; // number | boolean
|
|
}
|
|
if (typeof strOrNumOrBool === "number") {
|
|
num = strOrNumOrBool; // number
|
|
}
|
|
else {
|
|
strOrBool = strOrNumOrBool; // string | boolean
|
|
}
|
|
if (typeof numOrC === "number") {
|
|
num = numOrC; // number
|
|
}
|
|
else {
|
|
c = numOrC; // C
|
|
}
|
|
|
|
if (typeof strOrBool === "number") {
|
|
let y1: {} = strOrBool; // {}
|
|
}
|
|
else {
|
|
let y2: string | boolean = strOrBool; // string | boolean
|
|
}
|
|
|
|
// A type guard of the form typeof x !== s, where s is a string literal,
|
|
// - when true, narrows the type of x by typeof x === s when false, or
|
|
// - when false, narrows the type of x by typeof x === s when true.
|
|
if (typeof strOrNum !== "number") {
|
|
str === strOrNum; // string
|
|
}
|
|
else {
|
|
num = strOrNum; // number
|
|
}
|
|
if (typeof numOrBool !== "number") {
|
|
var x: number | boolean = numOrBool; // number | boolean
|
|
}
|
|
else {
|
|
num = numOrBool; // number
|
|
}
|
|
if (typeof strOrNumOrBool !== "number") {
|
|
strOrBool = strOrNumOrBool; // string | boolean
|
|
}
|
|
else {
|
|
num = strOrNumOrBool; // number
|
|
}
|
|
if (typeof numOrC !== "number") {
|
|
c = numOrC; // C
|
|
}
|
|
else {
|
|
num = numOrC; // number
|
|
}
|
|
|
|
if (typeof strOrBool !== "number") {
|
|
let y1: string | boolean = strOrBool; // string | boolean
|
|
}
|
|
else {
|
|
let y2: {} = strOrBool; // {}
|
|
}
|