TypeScript/tests/baselines/reference/arrayFrom.js
2018-05-09 11:11:46 -07:00

76 lines
2.5 KiB
TypeScript

//// [arrayFrom.ts]
// Tests fix for #20432, ensures Array.from accepts all valid inputs
// Also tests for #19682
interface A {
a: string;
}
interface B {
b: string;
}
const inputA: A[] = [];
const inputB: B[] = [];
const inputALike: ArrayLike<A> = { length: 0 };
const inputARand = getEither(inputA, inputALike);
const inputASet = new Set<A>();
const result1: A[] = Array.from(inputA);
const result2: A[] = Array.from(inputA.values());
const result3: B[] = Array.from(inputA.values()); // expect error
const result4: A[] = Array.from(inputB, ({ b }): A => ({ a: b }));
const result5: A[] = Array.from(inputALike);
const result6: B[] = Array.from(inputALike); // expect error
const result7: B[] = Array.from(inputALike, ({ a }): B => ({ b: a }));
const result8: A[] = Array.from(inputARand);
const result9: B[] = Array.from(inputARand, ({ a }): B => ({ b: a }));
const result10: A[] = Array.from(new Set<A>());
const result11: B[] = Array.from(inputASet, ({ a }): B => ({ b: a }));
// if this is written inline, the compiler seems to infer
// the ?: as always taking the false branch, narrowing to ArrayLike<T>,
// even when the type is written as : Iterable<T>|ArrayLike<T>
function getEither<T> (in1: Iterable<T>, in2: ArrayLike<T>) {
return Math.random() > 0.5 ? in1 : in2;
}
//// [arrayFrom.js]
// Tests fix for #20432, ensures Array.from accepts all valid inputs
// Also tests for #19682
var inputA = [];
var inputB = [];
var inputALike = { length: 0 };
var inputARand = getEither(inputA, inputALike);
var inputASet = new Set();
var result1 = Array.from(inputA);
var result2 = Array.from(inputA.values());
var result3 = Array.from(inputA.values()); // expect error
var result4 = Array.from(inputB, function (_a) {
var b = _a.b;
return ({ a: b });
});
var result5 = Array.from(inputALike);
var result6 = Array.from(inputALike); // expect error
var result7 = Array.from(inputALike, function (_a) {
var a = _a.a;
return ({ b: a });
});
var result8 = Array.from(inputARand);
var result9 = Array.from(inputARand, function (_a) {
var a = _a.a;
return ({ b: a });
});
var result10 = Array.from(new Set());
var result11 = Array.from(inputASet, function (_a) {
var a = _a.a;
return ({ b: a });
});
// if this is written inline, the compiler seems to infer
// the ?: as always taking the false branch, narrowing to ArrayLike<T>,
// even when the type is written as : Iterable<T>|ArrayLike<T>
function getEither(in1, in2) {
return Math.random() > 0.5 ? in1 : in2;
}