79 lines
No EOL
2.4 KiB
TypeScript
79 lines
No EOL
2.4 KiB
TypeScript
// typeguards are scoped in function/module block
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function foo(x: number | string | boolean) {
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return typeof x === "string"
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? x
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: function f() {
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var b = x; // number | boolean
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return typeof x === "boolean"
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? x.toString() // boolean
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: x.toString(); // number
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} ();
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}
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function foo2(x: number | string | boolean) {
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return typeof x === "string"
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? x
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: function f(a: number | boolean) {
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var b = x; // new scope - number | boolean
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return typeof x === "boolean"
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? x.toString() // boolean
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: x.toString(); // number
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} (x); // x here is narrowed to number | boolean
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}
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function foo3(x: number | string | boolean) {
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return typeof x === "string"
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? x
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: (() => {
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var b = x; // new scope - number | boolean
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return typeof x === "boolean"
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? x.toString() // boolean
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: x.toString(); // number
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})();
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}
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function foo4(x: number | string | boolean) {
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return typeof x === "string"
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? x
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: ((a: number | boolean) => {
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var b = x; // new scope - number | boolean
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return typeof x === "boolean"
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? x.toString() // boolean
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: x.toString(); // number
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})(x); // x here is narrowed to number | boolean
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}
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// Type guards do not affect nested function declarations
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function foo5(x: number | string | boolean) {
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if (typeof x === "string") {
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var y = x; // string;
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function foo() {
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var z = x; // string
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}
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}
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}
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module m {
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var x: number | string | boolean;
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module m2 {
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var b = x; // new scope - number | boolean | string
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var y: string;
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if (typeof x === "string") {
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y = x // string;
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} else {
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y = typeof x === "boolean"
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? x.toString() // boolean
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: x.toString(); // number
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}
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}
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}
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module m1 {
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var x: number | string | boolean;
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module m2.m3 {
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var b = x; // new scope - number | boolean | string
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var y: string;
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if (typeof x === "string") {
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y = x // string;
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} else {
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y = typeof x === "boolean"
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? x.toString() // boolean
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: x.toString(); // number
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}
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}
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} |