swc/crates/swc_ecma_parser/tests/tsc/arrayLiterals3.ts

35 lines
2.0 KiB
TypeScript

// Each element expression in a non-empty array literal is processed as follows:
// - If the array literal contains no spread elements, and if the array literal is contextually typed (section 4.19)
// by a type T and T has a property with the numeric name N, where N is the index of the element expression in the array literal,
// the element expression is contextually typed by the type of that property.
// The resulting type an array literal expression is determined as follows:
// - If the array literal contains no spread elements and is contextually typed by a tuple-like type,
// the resulting type is a tuple type constructed from the types of the element expressions.
var a0: [any, any, any] = []; // Error
var a1: [boolean, string, number] = ["string", 1, true]; // Error
// The resulting type an array literal expression is determined as follows:
// - If the array literal contains no spread elements and is an array assignment pattern in a destructuring assignment (section 4.17.1),
// the resulting type is a tuple type constructed from the types of the element expressions.
var [b1, b2]: [number, number] = [1, 2, "string", true];
// The resulting type an array literal expression is determined as follows:
// - the resulting type is an array type with an element type that is the union of the types of the
// non - spread element expressions and the numeric index signature types of the spread element expressions
var temp = ["s", "t", "r"];
var temp1 = [1, 2, 3];
var temp2: [number[], string[]] = [[1, 2, 3], ["hello", "string"]];
interface tup {
0: number[]|string[];
1: number[]|string[];
}
interface myArray extends Array<Number> { }
interface myArray2 extends Array<Number|String> { }
var c0: tup = [...temp2]; // Error
var c1: [number, number, number] = [...temp1]; // Error cannot assign number[] to [number, number, number]
var c2: myArray = [...temp1, ...temp]; // Error cannot assign (number|string)[] to number[]