load("test-common.js"); try { assert(Array.prototype.map.length === 1); assertThrowsError(() => { [].map(); }, { error: TypeError, message: "Array.prototype.map() requires at least one argument" }); assertThrowsError(() => { [].map(undefined); }, { error: TypeError, message: "undefined is not a function" }); var callbackCalled = 0; var callback = () => { callbackCalled++; }; assert([].map(callback).length === 0); assert(callbackCalled === 0); assert([1, 2, 3].map(callback).length === 3); assert(callbackCalled === 3); callbackCalled = 0; assert([1, , , "foo", , undefined, , ,].map(callback).length === 8); assert(callbackCalled === 3); var results = [undefined, null, true, "foo", 42, {}].map((value, index) => "" + index + " -> " + value); assert(results.length === 6); assert(results[0] === "0 -> undefined"); assert(results[1] === "1 -> null"); assert(results[2] === "2 -> true"); assert(results[3] === "3 -> foo"); assert(results[4] === "4 -> 42"); assert(results[5] === "5 -> [object Object]"); var squaredNumbers = [0, 1, 2, 3, 4].map(x => x ** 2); assert(squaredNumbers.length === 5); assert(squaredNumbers[0] === 0); assert(squaredNumbers[1] === 1); assert(squaredNumbers[2] === 4); assert(squaredNumbers[3] === 9); assert(squaredNumbers[4] === 16); console.log("PASS"); } catch (e) { console.log("FAIL: " + e); }