// Copyright 2016 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. (function TestMeta() { assertEquals(1, String.prototype.padStart.length); assertEquals("function", typeof String.prototype.padStart); assertEquals(Object.getPrototypeOf(Function), Object.getPrototypeOf(String.prototype.padStart)); assertEquals("padStart", String.prototype.padStart.name); var desc = Object.getOwnPropertyDescriptor(String.prototype, "padStart"); assertFalse(desc.enumerable); assertTrue(desc.configurable); assertTrue(desc.writable); assertEquals(undefined, desc.get); assertEquals(undefined, desc.set); assertThrows(() => new Function(`${String.prototype.padStart}`), SyntaxError); })(); (function TestRequireObjectCoercible() { var padStart = String.prototype.padStart; assertThrows(() => padStart.call(null, 4, "test"), TypeError); assertThrows(() => padStart.call(undefined, 4, "test"), TypeError); assertEquals(" 123", padStart.call({ __proto__: null, valueOf() { return 123; } }, 6, " ")); var proxy = new Proxy({}, { get(t, name) { if (name === Symbol.toPrimitive || name === "toString") return; if (name === "valueOf") return () => 6.7; assertUnreachable(); } }); assertEquals(" 6.7", padStart.call(proxy, 6, " ")); proxy = new Proxy({}, { get(t, name) { if (name === Symbol.toPrimitive || name === "valueOf") return; if (name === "toString") return () => 6.7; assertUnreachable(); } }); assertEquals(" 6.7", padStart.call(proxy, 6, " ")); })(); (function TestToLength() { assertThrows(() => "123".padStart(Symbol("16")), TypeError); assertEquals("123", "123".padStart(-1)); assertEquals("123", "123".padStart({ toString() { return -1; } })); assertEquals("123", "123".padStart(-0)); assertEquals("123", "123".padStart({ toString() { return -0; } })); assertEquals("123", "123".padStart(+0)); assertEquals("123", "123".padStart({ toString() { return +0; } })); assertEquals("123", "123".padStart(NaN)); assertEquals("123", "123".padStart({ toString() { return NaN; } })); })(); (function TestFillerToString() { assertEquals(" .", ".".padStart(10)); assertEquals(" .", ".".padStart(10, undefined)); assertEquals("nullnulln.", ".".padStart(10, null)); assertEquals("XXXXXXXXX.", ".".padStart(10, { toString() { return "X"; } })); assertEquals( "111111111.", ".".padStart(10, { toString: undefined, valueOf() { return 1; } })); })(); (function TestFillerEmptyString() { assertEquals(".", ".".padStart(10, "")); assertEquals(".", ".".padStart(10, { toString() { return ""; } })); assertEquals( ".", ".".padStart(10, { toString: undefined, valueOf() { return ""; } })); })(); (function TestFillerRepetition() { for (var i = 2000; i > 0; --i) { var expected = "xoxo".repeat(i / 4).slice(0, i - 3) + "123"; var actual = "123".padStart(i, "xoxo"); assertEquals(expected, actual); assertEquals(i > "123".length ? i : 3, actual.length); } })(); (function TestTruncation() { assertEquals("ba", "a".padStart(2, "bc")); })(); (function TestMaxLength() { assertThrows(() => "123".padStart(Math.pow(2, 40)), RangeError); assertThrows(() => "123".padStart(1 << 30), RangeError); })(); (function TestNoArguments() { assertEquals("abc", "abc".padStart()); })();