diff --git a/Userland/Libraries/LibJS/Runtime/ArrayConstructor.cpp b/Userland/Libraries/LibJS/Runtime/ArrayConstructor.cpp index b3c495950e..a620ff99e8 100644 --- a/Userland/Libraries/LibJS/Runtime/ArrayConstructor.cpp +++ b/Userland/Libraries/LibJS/Runtime/ArrayConstructor.cpp @@ -105,6 +105,8 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from) map_fn = &callback.as_function(); } + auto this_arg = vm.argument(2); + // Array.from() lets you create Arrays from: if (auto size = object->indexed_properties().array_like_size()) { // * array-like objects (objects with a length property and indexed elements) @@ -116,7 +118,7 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from) if (vm.exception()) return {}; - auto map_fn_result = vm.call(*map_fn, value, element); + auto map_fn_result = vm.call(*map_fn, this_arg, element, Value((i32)i)); if (vm.exception()) return {}; @@ -130,12 +132,14 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from) array->set_indexed_property_elements(move(elements)); } else { // * iterable objects + i32 i = 0; get_iterator_values(global_object, value, [&](Value element) { if (vm.exception()) return IterationDecision::Break; if (map_fn) { - auto map_fn_result = vm.call(*map_fn, value, element); + auto map_fn_result = vm.call(*map_fn, this_arg, element, Value(i)); + i++; if (vm.exception()) return IterationDecision::Break; @@ -150,8 +154,6 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from) return {}; } - // FIXME: if interpreter.argument_count() >= 3: thisArg - return array; } diff --git a/Userland/Libraries/LibJS/Tests/builtins/Array/Array.from.js b/Userland/Libraries/LibJS/Tests/builtins/Array/Array.from.js index 0c8562ceb5..f6867ba390 100644 --- a/Userland/Libraries/LibJS/Tests/builtins/Array/Array.from.js +++ b/Userland/Libraries/LibJS/Tests/builtins/Array/Array.from.js @@ -9,24 +9,48 @@ describe("normal behavior", () => { expect(a).toHaveLength(0); }); - test("empty array, with mapFn", () => { + test("empty array, with mapFn, no thisArg", () => { const a = Array.from([], n => n); expect(a instanceof Array).toBeTrue(); expect(a).toHaveLength(0); }); + test("empty array, with mapFn, with thisArg", () => { + const a = Array.from( + [], + function (n) { + return n + this.value; + }, + { value: 100 } + ); + expect(a instanceof Array).toBeTrue(); + expect(a).toHaveLength(0); + }); + test("empty string, no mapFn", () => { const a = Array.from(""); expect(a instanceof Array).toBeTrue(); expect(a).toHaveLength(0); }); - test("empty string, with mapFn", () => { + test("empty string, with mapFn, no thisArg", () => { const a = Array.from("", n => n); expect(a instanceof Array).toBeTrue(); expect(a).toHaveLength(0); }); + test("empty string, with mapFn, with thisArg", () => { + const a = Array.from( + "", + function (n) { + return n + this.value; + }, + { value: 100 } + ); + expect(a instanceof Array).toBeTrue(); + expect(a).toHaveLength(0); + }); + test("non-empty array, no mapFn", () => { const a = Array.from([5, 8, 1]); expect(a instanceof Array).toBeTrue(); @@ -36,13 +60,28 @@ describe("normal behavior", () => { expect(a[2]).toBe(1); }); - test("non-empty array, with mapFn", () => { - const a = Array.from([5, 8, 1], n => ++n); + test("non-empty array, with mapFn, no thisArg", () => { + const a = Array.from([5, 8, 1], (n, i) => n - i); expect(a instanceof Array).toBeTrue(); expect(a).toHaveLength(3); - expect(a[0]).toBe(6); - expect(a[1]).toBe(9); - expect(a[2]).toBe(2); + expect(a[0]).toBe(5); + expect(a[1]).toBe(7); + expect(a[2]).toBe(-1); + }); + + test("non-empty array, with mapFn, with thisArg", () => { + const a = Array.from( + [5, 8, 1], + function (n, i) { + return n - i + this.value; + }, + { value: 100 } + ); + expect(a instanceof Array).toBeTrue(); + expect(a).toHaveLength(3); + expect(a[0]).toBe(105); + expect(a[1]).toBe(107); + expect(a[2]).toBe(99); }); test("non-empty string, no mapFn", () => { @@ -55,14 +94,30 @@ describe("normal behavior", () => { expect(a[3]).toBe("t"); }); - test("non-empty string, with mapFn", () => { - const a = Array.from("what", n => n + n); + test("non-empty string, with mapFn, no thisArg", () => { + const a = Array.from("what", (n, i) => n + n + i); expect(a instanceof Array).toBeTrue(); expect(a).toHaveLength(4); - expect(a[0]).toBe("ww"); - expect(a[1]).toBe("hh"); - expect(a[2]).toBe("aa"); - expect(a[3]).toBe("tt"); + expect(a[0]).toBe("ww0"); + expect(a[1]).toBe("hh1"); + expect(a[2]).toBe("aa2"); + expect(a[3]).toBe("tt3"); + }); + + test("non-empty string, with mapFn, with thisArg", () => { + const a = Array.from( + "what", + function (n, i) { + return n + i + this.value; + }, + { value: "a" } + ); + expect(a instanceof Array).toBeTrue(); + expect(a).toHaveLength(4); + expect(a[0]).toBe("w0a"); + expect(a[1]).toBe("h1a"); + expect(a[2]).toBe("a2a"); + expect(a[3]).toBe("t3a"); }); test("shallow array copy, no mapFn", () => { @@ -74,7 +129,7 @@ describe("normal behavior", () => { expect(a[0]).toBe(4); }); - test("shallow array copy, with mapFn", () => { + test("shallow array copy, with mapFn, no thisArg", () => { const a = [1, 2, 3]; const b = Array.from([a], n => n.map(n => n + 2)); expect(b instanceof Array).toBeTrue(); @@ -86,6 +141,24 @@ describe("normal behavior", () => { expect(b[0][2]).toBe(5); }); + test("shallow array copy, with mapFn, with thisArg", () => { + const a = [1, 2, 3]; + const b = Array.from( + [a], + function (n, i) { + return n.map(n => n + 2 + i + this.value); + }, + { value: 100 } + ); + expect(b instanceof Array).toBeTrue(); + expect(b).toHaveLength(1); + b[0][0] = 10; + expect(a[0]).toBe(1); + expect(b[0][0]).toBe(10); + expect(b[0][1]).toBe(104); + expect(b[0][2]).toBe(105); + }); + const rangeIterator = function (begin, end) { return { [Symbol.iterator]() { @@ -110,11 +183,25 @@ describe("normal behavior", () => { expect(a[1]).toBe(9); }); - test("from iterator, with mapFn", () => { + test("from iterator, with mapFn, no thisArg", () => { const a = Array.from(rangeIterator(8, 10), n => --n); expect(a instanceof Array).toBeTrue(); expect(a).toHaveLength(2); expect(a[0]).toBe(7); expect(a[1]).toBe(8); }); + + test("from iterator, with mapFn, with thisArg", () => { + const a = Array.from( + rangeIterator(8, 10), + function (n, i) { + return n + i + this.value; + }, + { value: 100 } + ); + expect(a instanceof Array).toBeTrue(); + expect(a).toHaveLength(2); + expect(a[0]).toBe(108); + expect(a[1]).toBe(110); + }); });