67 lines
No EOL
1.4 KiB
TypeScript
67 lines
No EOL
1.4 KiB
TypeScript
// A type guard of the form x instanceof C, where C is of a subtype of the global type 'Function'
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// and C has a property named 'prototype'
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// - when true, narrows the type of x to the type of the 'prototype' property in C provided
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// it is a subtype of the type of x, or
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// - when false, has no effect on the type of x.
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class C1 {
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p1: string;
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}
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class C2 {
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p2: number;
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}
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class D1 extends C1 {
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p3: number;
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}
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class C3 {
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p4: number;
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}
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var str: string;
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var num: number;
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var strOrNum: string | number;
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var ctor1: C1 | C2;
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str = ctor1 instanceof C1 && ctor1.p1; // C1
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num = ctor1 instanceof C2 && ctor1.p2; // C2
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str = ctor1 instanceof D1 && ctor1.p1; // D1
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num = ctor1 instanceof D1 && ctor1.p3; // D1
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var ctor2: C2 | D1;
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num = ctor2 instanceof C2 && ctor2.p2; // C2
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num = ctor2 instanceof D1 && ctor2.p3; // D1
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str = ctor2 instanceof D1 && ctor2.p1; // D1
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var r2: D1 | C2 = ctor2 instanceof C1 && ctor2; // C2 | D1
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var ctor3: C1 | C2;
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if (ctor3 instanceof C1) {
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ctor3.p1; // C1
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}
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else {
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ctor3.p2; // C2
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}
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var ctor4: C1 | C2 | C3;
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if (ctor4 instanceof C1) {
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ctor4.p1; // C1
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}
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else if (ctor4 instanceof C2) {
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ctor4.p2; // C2
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}
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else {
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ctor4.p4; // C3
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}
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var ctor5: C1 | D1 | C2;
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if (ctor5 instanceof C1) {
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ctor5.p1; // C1
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}
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else {
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ctor5.p2; // C2
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}
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var ctor6: C1 | C2 | C3;
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if (ctor6 instanceof C1 || ctor6 instanceof C2) {
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}
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else {
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ctor6.p4; // C3
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} |