42 lines
2.4 KiB
TypeScript
42 lines
2.4 KiB
TypeScript
// @downlevelIteration: true
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// The type T associated with a destructuring variable declaration is determined as follows:
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// If the declaration includes a type annotation, T is that type.
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var {a1, a2}: { a1: number, a2: string } = { a1: 10, a2: "world" }
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var [a3, [[a4]], a5]: [number, [[string]], boolean] = [1, [["hello"]], true];
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// The type T associated with a destructuring variable declaration is determined as follows:
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// Otherwise, if the declaration includes an initializer expression, T is the type of that initializer expression.
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var { b1: { b11 } = { b11: "string" } } = { b1: { b11: "world" } };
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var temp = { t1: true, t2: "false" };
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var [b2 = 3, b3 = true, b4 = temp] = [3, false, { t1: false, t2: "hello" }];
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var [b5 = 3, b6 = true, b7 = temp] = [undefined, undefined, undefined];
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// The type T associated with a binding element is determined as follows:
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// If the binding element is a rest element, T is an array type with
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// an element type E, where E is the type of the numeric index signature of S.
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var [...c1] = [1,2,3];
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var [...c2] = [1,2,3, "string"];
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// The type T associated with a binding element is determined as follows:
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// Otherwise, if S is a tuple- like type (section 3.3.3):
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// Let N be the zero-based index of the binding element in the array binding pattern.
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// If S has a property with the numerical name N, T is the type of that property.
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var [d1,d2] = [1,"string"]
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// The type T associated with a binding element is determined as follows:
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// Otherwise, if S is a tuple- like type (section 3.3.3):
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// Otherwise, if S has a numeric index signature, T is the type of the numeric index signature.
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var temp1 = [true, false, true]
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var [d3, d4] = [1, "string", ...temp1];
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// Combining both forms of destructuring,
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var {e: [e1, e2, e3 = { b1: 1000, b4: 200 }]} = { e: [1, 2, { b1: 4, b4: 0 }] };
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var {f: [f1, f2, { f3: f4, f5 }, , ]} = { f: [1, 2, { f3: 4, f5: 0 }] };
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// When a destructuring variable declaration, binding property, or binding element specifies
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// an initializer expression, the type of the initializer expression is required to be assignable
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// to the widened form of the type associated with the destructuring variable declaration, binding property, or binding element.
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var {g: {g1 = [undefined, null]}}: { g: { g1: any[] } } = { g: { g1: [1, 2] } };
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var {h: {h1 = [undefined, null]}}: { h: { h1: number[] } } = { h: { h1: [1, 2] } };
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