153 lines
3 KiB
TypeScript
153 lines
3 KiB
TypeScript
//// [typeGuardFunction.ts]
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class A {
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propA: number;
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}
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class B {
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propB: number;
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}
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class C extends A {
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propC: number;
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}
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declare function isA(p1: any): p1 is A;
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declare function isB(p1: any): p1 is B;
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declare function isC(p1: any): p1 is C;
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declare function retC(): C;
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var a: A;
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var b: B;
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// Basic
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if (isC(a)) {
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a.propC;
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}
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// Sub type
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var subType: C;
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if(isA(subType)) {
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subType.propC;
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}
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// Union type
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var union: A | B;
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if(isA(union)) {
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union.propA;
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}
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// Call signature
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interface I1 {
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(p1: A): p1 is C;
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}
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// The parameter index and argument index for the type guard target is matching.
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// The type predicate type is assignable to the parameter type.
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declare function isC_multipleParams(p1, p2): p1 is C;
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if (isC_multipleParams(a, 0)) {
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a.propC;
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}
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// Methods
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var obj: {
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func1(p1: A): p1 is C;
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}
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class D {
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method1(p1: A): p1 is C {
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return true;
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}
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}
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// Arrow function
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let f1 = (p1: A): p1 is C => false;
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// Function type
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declare function f2(p1: (p1: A) => p1 is C);
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// Function expressions
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f2(function(p1: A): p1 is C {
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return true;
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});
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// Evaluations are asssignable to boolean.
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declare function acceptingBoolean(a: boolean);
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acceptingBoolean(isA(a));
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// Type predicates with different parameter name.
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declare function acceptingTypeGuardFunction(p1: (item) => item is A);
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acceptingTypeGuardFunction(isA);
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// Binary expressions
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let union2: C | B;
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let union3: boolean | B = isA(union2) || union2;
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//// [typeGuardFunction.js]
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var __extends = (this && this.__extends) || (function () {
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var extendStatics = Object.setPrototypeOf ||
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({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
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function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
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return function (d, b) {
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extendStatics(d, b);
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function __() { this.constructor = d; }
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d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
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};
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})();
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var A = /** @class */ (function () {
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function A() {
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}
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return A;
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}());
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var B = /** @class */ (function () {
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function B() {
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}
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return B;
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}());
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var C = /** @class */ (function (_super) {
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__extends(C, _super);
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function C() {
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return _super !== null && _super.apply(this, arguments) || this;
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}
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return C;
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}(A));
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var a;
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var b;
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// Basic
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if (isC(a)) {
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a.propC;
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}
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// Sub type
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var subType;
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if (isA(subType)) {
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subType.propC;
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}
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// Union type
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var union;
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if (isA(union)) {
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union.propA;
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}
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if (isC_multipleParams(a, 0)) {
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a.propC;
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}
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// Methods
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var obj;
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var D = /** @class */ (function () {
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function D() {
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}
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D.prototype.method1 = function (p1) {
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return true;
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};
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return D;
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}());
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// Arrow function
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var f1 = function (p1) { return false; };
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// Function expressions
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f2(function (p1) {
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return true;
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});
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acceptingBoolean(isA(a));
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acceptingTypeGuardFunction(isA);
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// Binary expressions
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var union2;
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var union3 = isA(union2) || union2;
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