Coverage: Array.prototype.item, String.prototype.item, TypedArray.prototype.item. Closes gh-2809, gh-2810, gh-2811

features.txt

@@ -182,6 +182,12 @@ logical-assignment-operators
 # https://github.com/tc39/proposal-atomics-wait-async
 Atomics.waitAsync
 
+# Item Method
+# https://github.com/tc39/proposal-item-method
+Array.prototype.item
+String.prototype.item
+TypedArray.prototype.item
+
 ## Standard language features
 #
 # Language features that have been included in a published version of the

test/built-ins/Array/prototype/item/index-argument-tointeger.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  Array.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+let valueOfCallCount = 0;
+let index = {
+  valueOf() {
+    valueOfCallCount++;
+    return 1;
+  }
+};
+
+let a = [0,1,2,3];
+
+assert.sameValue(a.item(index), 1, 'a.item({valueOf() {valueOfCallCount++; return 1;}}) must return 1');
+assert.sameValue(valueOfCallCount, 1, 'The value of `valueOfCallCount` is 1');

test/built-ins/Array/prototype/item/index-non-numeric-argument-tointeger-invalid.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  Array.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+let a = [0,1,2,3];
+
+assert.throws(TypeError, () => {
+  a.item(Symbol());
+}, '`a.item(Symbol())` throws TypeError');

test/built-ins/Array/prototype/item/index-non-numeric-argument-tointeger.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  Array.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+let a = [0,1,2,3];
+
+assert.sameValue(a.item(false), 0, 'a.item(false) must return 0');
+assert.sameValue(a.item(null), 0, 'a.item(null) must return 0');
+assert.sameValue(a.item(undefined), 0, 'a.item(undefined) must return 0');
+assert.sameValue(a.item(""), 0, 'a.item("") must return 0');
+assert.sameValue(a.item(function() {}), 0, 'a.item(function() {}) must return 0');
+assert.sameValue(a.item([]), 0, 'a.item([]) must return 0');
+
+assert.sameValue(a.item(true), 1, 'a.item(true) must return 1');
+assert.sameValue(a.item("1"), 1, 'a.item("1") must return 1');

test/built-ins/Array/prototype/item/length.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Array.prototype.item.length value and descriptor.
+info: |
+  Array.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js]
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+assert.sameValue(
+  Array.prototype.item.length, 1,
+  'The value of Array.prototype.item.length is 1'
+);
+
+verifyNotEnumerable(Array.prototype.item, 'length');
+verifyNotWritable(Array.prototype.item, 'length');
+verifyConfigurable(Array.prototype.item, 'length');

test/built-ins/Array/prototype/item/name.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Array.prototype.item.name value and descriptor.
+info: |
+  Array.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js]
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+assert.sameValue(
+  Array.prototype.item.name, 'item',
+  'The value of Array.prototype.item.name is "item"'
+);
+
+verifyNotEnumerable(Array.prototype.item, 'name');
+verifyNotWritable(Array.prototype.item, 'name');
+verifyConfigurable(Array.prototype.item, 'name');

test/built-ins/Array/prototype/item/prop-desc.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  Array.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+includes: [propertyHelper.js]
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+assert.sameValue(
+  typeof Array.prototype.item,
+  'function',
+  'The value of `typeof Array.prototype.item` is "function"'
+);
+
+verifyNotEnumerable(Array.prototype, 'item');
+verifyWritable(Array.prototype, 'item');
+verifyConfigurable(Array.prototype, 'item');

test/built-ins/Array/prototype/item/return-abrupt-from-this.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Return abrupt from ToObject(this value).
+info: |
+  Array.prototype.item( index )
+
+  Let O be ? ToObject(this value).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+assert.throws(TypeError, () => {
+  Array.prototype.item.call(undefined);
+}, '`Array.prototype.item.call(undefined)` throws TypeError');
+
+assert.throws(TypeError, () => {
+  Array.prototype.item.call(null);
+}, '`Array.prototype.item.call(null)` throws TypeError');

test/built-ins/Array/prototype/item/returns-item-relative-index.js

@@ -0,0 +1,30 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Returns the item value at the specified relative index
+info: |
+  Array.prototypeitem ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfArrayLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+let a = [1, 2, 3, 4, ,5];
+
+assert.sameValue(a.item(0), 1, 'a.item(0) must return 1');
+assert.sameValue(a.item(-1), 5, 'a.item(-1) must return 5');
+assert.sameValue(a.item(-2), undefined, 'a.item(-2) must return undefined');
+assert.sameValue(a.item(-3), 4, 'a.item(-3) must return 4');
+assert.sameValue(a.item(-4), 3, 'a.item(-4) must return 3');

test/built-ins/Array/prototype/item/returns-item.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Returns the item value at the specified index
+info: |
+  Array.prototypeitem ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfArrayLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+let a = [1, 2, 3, 4,,5];
+
+assert.sameValue(a.item(0), 1, 'a.item(0) must return 1');
+assert.sameValue(a.item(1), 2, 'a.item(1) must return 2');
+assert.sameValue(a.item(2), 3, 'a.item(2) must return 3');
+assert.sameValue(a.item(3), 4, 'a.item(3) must return 4');
+assert.sameValue(a.item(4), undefined, 'a.item(4) must return undefined');
+assert.sameValue(a.item(5), 5, 'a.item(5) must return 5');

test/built-ins/Array/prototype/item/returns-undefined-for-holes-in-sparse-arrays.js

@@ -0,0 +1,43 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Returns the item value at the specified index, respecting holes in sparse arrays.
+info: |
+  Array.prototypeitem ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfArrayLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [Array.prototype.item]
+---*/
+assert.sameValue(
+  typeof Array.prototype.item,
+  'function',
+  'The value of `typeof Array.prototype.item` is "function"'
+);
+
+let a = [0, 1, , 3, 4, , 6];
+
+assert.sameValue(a.item(0), 0, 'a.item(0) must return 0');
+assert.sameValue(a.item(1), 1, 'a.item(1) must return 1');
+assert.sameValue(a.item(2), undefined, 'a.item(2) must return undefined');
+assert.sameValue(a.item(3), 3, 'a.item(3) must return 3');
+assert.sameValue(a.item(4), 4, 'a.item(4) must return 4');
+assert.sameValue(a.item(5), undefined, 'a.item(5) must return undefined');
+assert.sameValue(a.item(6), 6, 'a.item(6) must return 6');
+assert.sameValue(a.item(-0), 0, 'a.item(-0) must return 0');
+assert.sameValue(a.item(-1), 6, 'a.item(-1) must return 6');
+assert.sameValue(a.item(-2), undefined, 'a.item(-2) must return undefined');
+assert.sameValue(a.item(-3), 4, 'a.item(-3) must return 4');
+assert.sameValue(a.item(-4), 3, 'a.item(-4) must return 3');
+assert.sameValue(a.item(-5), undefined, 'a.item(-5) must return undefined');
+assert.sameValue(a.item(-6), 1, 'a.item(-6) must return 1');

test/built-ins/Array/prototype/item/returns-undefined-for-out-of-range-index.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.item
+description: >
+  Returns undefined if the specified index less than or greater than the available index range.
+info: |
+  Array.prototype.item( index )
+
+  If k < 0 or k ≥ len, then return undefined.
+features: [Array.prototype.item]
+---*/
+assert.sameValue(typeof Array.prototype.item, 'function');
+
+let a = [];
+
+assert.sameValue(a.item(-2), undefined, 'a.item(-2) must return undefined'); // wrap around the end
+assert.sameValue(a.item(0), undefined, 'a.item(0) must return undefined');
+assert.sameValue(a.item(1), undefined, 'a.item(1) must return undefined');
+

test/built-ins/String/prototype/item/index-argument-tointeger.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  String.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let valueOfCallCount = 0;
+let index = {
+  valueOf() {
+    valueOfCallCount++;
+    return 1;
+  }
+};
+
+let s = "01";
+
+assert.sameValue(s.item(index), '1', 's.item({valueOf() {valueOfCallCount++; return 1;}}) must return 1');
+assert.sameValue(valueOfCallCount, 1, 'The value of `valueOfCallCount` is 1');

test/built-ins/String/prototype/item/index-non-numeric-argument-tointeger-invalid.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  String.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let s = "01";
+
+assert.throws(TypeError, () => {
+  s.item(Symbol());
+}, '`s.item(Symbol())` throws TypeError');

test/built-ins/String/prototype/item/index-non-numeric-argument-tointeger.js

@@ -0,0 +1,26 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  String.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let s = "01";
+
+assert.sameValue(s.item(false), '0', 's.item(false) must return 0');
+assert.sameValue(s.item(null), '0', 's.item(null) must return 0');
+assert.sameValue(s.item(undefined), '0', 's.item(undefined) must return 0');
+assert.sameValue(s.item(""), '0', 's.item("") must return 0');
+assert.sameValue(s.item(function() {}), '0', 's.item(function() {}) must return 0');
+assert.sameValue(s.item([]), '0', 's.item([]) must return 0');
+
+assert.sameValue(s.item(true), '1', 's.item(true) must return 1');
+assert.sameValue(s.item("1"), '1', 's.item("1") must return 1');

test/built-ins/String/prototype/item/length.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  String.prototype.item.length value and descriptor.
+info: |
+  String.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js]
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+assert.sameValue(
+  String.prototype.item.length, 1,
+  'The value of String.prototype.item.length is 1'
+);
+
+verifyNotEnumerable(String.prototype.item, 'length');
+verifyNotWritable(String.prototype.item, 'length');
+verifyConfigurable(String.prototype.item, 'length');

test/built-ins/String/prototype/item/name.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  String.prototype.item.name value and descriptor.
+info: |
+  String.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js]
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+assert.sameValue(
+  String.prototype.item.name, 'item',
+  'The value of String.prototype.item.name is "item"'
+);
+
+verifyNotEnumerable(String.prototype.item, 'name');
+verifyNotWritable(String.prototype.item, 'name');
+verifyConfigurable(String.prototype.item, 'name');

test/built-ins/String/prototype/item/prop-desc.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  String.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+includes: [propertyHelper.js]
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+assert.sameValue(
+  typeof String.prototype.item,
+  'function',
+  'The value of `typeof String.prototype.item` is "function"'
+);
+
+verifyNotEnumerable(String.prototype, 'item');
+verifyWritable(String.prototype, 'item');
+verifyConfigurable(String.prototype, 'item');

test/built-ins/String/prototype/item/return-abrupt-from-this.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  Return abrupt from RequireObjectCoercible(this value).
+info: |
+  String.prototype.item( index )
+
+  Let O be ? RequireObjectCoercible(this value).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+assert.throws(TypeError, () => {
+  String.prototype.item.call(undefined);
+}, '`String.prototype.item.call(undefined)` throws TypeError');
+
+assert.throws(TypeError, () => {
+  String.prototype.item.call(null);
+}, '`String.prototype.item.call(null)` throws TypeError');

test/built-ins/String/prototype/item/returns-code-unit.js

@@ -0,0 +1,30 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-String.prototype.item
+description: >
+  The method should return an Iterator instance.
+info: |
+  String.prototypeitem ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfStringLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let s = "12\uD80034";
+
+assert.sameValue(s.item(0), "1", 's.item(0) must return "1"');
+assert.sameValue(s.item(1), "2", 's.item(1) must return "2"');
+assert.sameValue(s.item(2), "\uD800", 's.item(2) must return "\\uD800"');
+assert.sameValue(s.item(3), "3", 's.item(3) must return "3"');
+assert.sameValue(s.item(4), "4", 's.item(4) must return "4"');

test/built-ins/String/prototype/item/returns-item-relative-index.js

@@ -0,0 +1,29 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-String.prototypeitem
+description: >
+  Returns the item value at the specified relative index
+info: |
+  String.prototypeitem ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfStringLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let s = "12345";
+
+assert.sameValue(s.item(0), "1", 's.item(0) must return "1"');
+assert.sameValue(s.item(-1), "5", 's.item(-1) must return "5"');
+assert.sameValue(s.item(-3), "3", 's.item(-3) must return "3"');
+assert.sameValue(s.item(-4), "2", 's.item(-4) must return "2"');

test/built-ins/String/prototype/item/returns-item.js

@@ -0,0 +1,30 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-String.prototypeitem
+description: >
+  Returns the item value at the specified index
+info: |
+  String.prototypeitem ( )
+
+  Let O be ? ToObject(this value).
+  Let len be ? LengthOfStringLike(O).
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let s = "12345";
+
+assert.sameValue(s.item(0), "1", 's.item(0) must return "1"');
+assert.sameValue(s.item(1), "2", 's.item(1) must return "2"');
+assert.sameValue(s.item(2), "3", 's.item(2) must return "3"');
+assert.sameValue(s.item(3), "4", 's.item(3) must return "4"');
+assert.sameValue(s.item(4), "5", 's.item(4) must return "5"');

test/built-ins/String/prototype/item/returns-undefined-for-out-of-range-index.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-string.prototype.item
+description: >
+  Creates an iterator from a custom object.
+info: |
+  String.prototype.item( index )
+
+  If k < 0 or k ≥ len, then return undefined.
+features: [String.prototype.item]
+---*/
+assert.sameValue(typeof String.prototype.item, 'function');
+
+let s = "";
+
+assert.sameValue(s.item(-2), undefined, 's.item(-2) must return undefined'); // wrap around the end
+assert.sameValue(s.item(0), undefined, 's.item(0) must return undefined');
+assert.sameValue(s.item(1), undefined, 's.item(1) must return undefined');
+

test/built-ins/TypedArray/prototype/item/index-argument-tointeger.js

@@ -0,0 +1,35 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+includes: [testTypedArray.js]
+features: [TypedArray, TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  assert.sameValue(typeof TA.prototype.item, 'function', 'The value of `typeof TA.prototype.item` is "function"');
+  let valueOfCallCount = 0;
+  let index = {
+    valueOf() {
+      valueOfCallCount++;
+      return 1;
+    }
+  };
+
+  let a = new TA([0,1,2,3]);
+
+  assert.sameValue(a.item(index), 1, 'a.item({valueOf() {valueOfCallCount++; return 1;}}) must return 1');
+  assert.sameValue(valueOfCallCount, 1, 'The value of `valueOfCallCount` is 1');
+});

test/built-ins/TypedArray/prototype/item/index-non-numeric-argument-tointeger-invalid.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+includes: [testTypedArray.js]
+features: [TypedArray, TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  assert.sameValue(typeof TA.prototype.item, 'function', 'The value of `typeof TA.prototype.item` is "function"');
+  let a = new TA([0,1,2,3]);
+
+  assert.throws(TypeError, () => {
+    a.item(Symbol());
+  }, '`a.item(Symbol())` throws TypeError');
+});

test/built-ins/TypedArray/prototype/item/index-non-numeric-argument-tointeger.js

@@ -0,0 +1,35 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let relativeIndex be ? ToInteger(index).
+
+includes: [testTypedArray.js]
+features: [TypedArray, TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  assert.sameValue(typeof TA.prototype.item, 'function', 'The value of `typeof TA.prototype.item` is "function"');
+
+  let a = new TA([0,1,2,3]);
+
+  assert.sameValue(a.item(false), 0, 'a.item(false) must return 0');
+  assert.sameValue(a.item(null), 0, 'a.item(null) must return 0');
+  assert.sameValue(a.item(undefined), 0, 'a.item(undefined) must return 0');
+  assert.sameValue(a.item(""), 0, 'a.item("") must return 0');
+  assert.sameValue(a.item(function() {}), 0, 'a.item(function() {}) must return 0');
+  assert.sameValue(a.item([]), 0, 'a.item([]) must return 0');
+
+  assert.sameValue(a.item(true), 1, 'a.item(true) must return 1');
+  assert.sameValue(a.item("1"), 1, 'a.item("1") must return 1');
+});

test/built-ins/TypedArray/prototype/item/length.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  TypedArray.prototype.item.length value and descriptor.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js, testTypedArray.js]
+features: [TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+assert.sameValue(
+  TypedArray.prototype.item.length, 1,
+  'The value of TypedArray.prototype.item.length is 1'
+);
+
+verifyNotEnumerable(TypedArray.prototype.item, 'length');
+verifyNotWritable(TypedArray.prototype.item, 'length');
+verifyConfigurable(TypedArray.prototype.item, 'length');

test/built-ins/TypedArray/prototype/item/name.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  %TypedArray%.prototype.item.name value and descriptor.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js, testTypedArray.js]
+features: [TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+assert.sameValue(
+  TypedArray.prototype.item.name, 'item',
+  'The value of TypedArray.prototype.item.name is "item"'
+);
+
+verifyNotEnumerable(TypedArray.prototype.item, 'name');
+verifyNotWritable(TypedArray.prototype.item, 'name');
+verifyConfigurable(TypedArray.prototype.item, 'name');

test/built-ins/TypedArray/prototype/item/prop-desc.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Property type and descriptor.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  17 ECMAScript Standard Built-in Objects
+includes: [propertyHelper.js, testTypedArray.js]
+features: [TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+verifyNotEnumerable(TypedArray.prototype, 'item');
+verifyWritable(TypedArray.prototype, 'item');
+verifyConfigurable(TypedArray.prototype, 'item');

test/built-ins/TypedArray/prototype/item/return-abrupt-from-this.js

@@ -0,0 +1,40 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Return abrupt from ToObject(this value).
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let O be the this value.
+  Perform ? ValidateTypedArray(O).
+
+includes: [testTypedArray.js]
+features: [TypedArray,TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+assert.throws(TypeError, () => {
+  TypedArray.prototype.item.call(undefined);
+}, '`TypedArray.prototype.item.call(undefined)` throws TypeError');
+
+assert.throws(TypeError, () => {
+  TypedArray.prototype.item.call(null);
+}, '`TypedArray.prototype.item.call(null)` throws TypeError');
+
+testWithTypedArrayConstructors(TA => {
+  assert.sameValue(typeof TA.prototype.item, 'function', 'The value of `typeof TA.prototype.item` is "function"');
+
+  assert.throws(TypeError, () => {
+    TA.prototype.item.call(undefined);
+  }, '`TA.prototype.item.call(undefined)` throws TypeError');
+
+  assert.throws(TypeError, () => {
+    TA.prototype.item.call(null);
+  }, '`TA.prototype.item.call(null)` throws TypeError');
+});

test/built-ins/TypedArray/prototype/item/returns-item-relative-index.js

@@ -0,0 +1,37 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Returns the item value at the specified relative index
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let O be the this value.
+  Perform ? ValidateTypedArray(O).
+  Let len be O.[[ArrayLength]].
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+includes: [testTypedArray.js]
+features: [TypedArray,TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  let a = new TA([1, 2, 3, 4, 5]);
+  assert.sameValue(a.item(0), 1, 'a.item(0) must return 1');
+  assert.sameValue(a.item(-1), 5, 'a.item(-1) must return 5');
+  assert.sameValue(a.item(-2), 4, 'a.item(-2) must return 4');
+  assert.sameValue(a.item(-3), 3, 'a.item(-3) must return 3');
+  assert.sameValue(a.item(-4), 2, 'a.item(-4) must return 2');
+});

test/built-ins/TypedArray/prototype/item/returns-item.js

@@ -0,0 +1,38 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Returns the item value at the specified index
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let O be the this value.
+  Perform ? ValidateTypedArray(O).
+  Let len be O.[[ArrayLength]].
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+includes: [testTypedArray.js]
+features: [TypedArray,TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  assert.sameValue(typeof TA.prototype.item, 'function', 'The value of `typeof TA.prototype.item` is "function"');
+  let a = new TA([1, 2, 3, 4]);
+
+  assert.sameValue(a.item(0), 1, 'a.item(0) must return 1');
+  assert.sameValue(a.item(1), 2, 'a.item(1) must return 2');
+  assert.sameValue(a.item(2), 3, 'a.item(2) must return 3');
+  assert.sameValue(a.item(3), 4, 'a.item(3) must return 4');
+});

test/built-ins/TypedArray/prototype/item/returns-undefined-for-holes-in-sparse-arrays.js

@@ -0,0 +1,50 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Returns the item value at the specified index, holes are filled in sparse arrays.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  Let O be the this value.
+  Perform ? ValidateTypedArray(O).
+  Let len be O.[[ArrayLength]].
+  Let relativeIndex be ? ToInteger(index).
+  If relativeIndex ≥ 0, then
+    Let k be relativeIndex.
+  Else,
+    Let k be len + relativeIndex.
+  If k < 0 or k ≥ len, then return undefined.
+  Return ? Get(O, ! ToString(k)).
+
+includes: [testTypedArray.js]
+features: [TypedArray, TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  let a = new TA([0, 1, , 3, 4, , 6]);
+  let filler = 0;
+  if (TA.name.startsWith('Float')) {
+    filler = NaN;
+  }
+  assert.sameValue(a.item(0), 0, 'a.item(0) must return 0');
+  assert.sameValue(a.item(1), 1, 'a.item(1) must return 1');
+  assert.sameValue(a.item(2), filler, 'a.item(2) must return the value of filler');
+  assert.sameValue(a.item(3), 3, 'a.item(3) must return 3');
+  assert.sameValue(a.item(4), 4, 'a.item(4) must return 4');
+  assert.sameValue(a.item(5), filler, 'a.item(5) must return the value of filler');
+  assert.sameValue(a.item(6), 6, 'a.item(6) must return 6');
+  assert.sameValue(a.item(-0), 0, 'a.item(-0) must return 0');
+  assert.sameValue(a.item(-1), 6, 'a.item(-1) must return 6');
+  assert.sameValue(a.item(-2), filler, 'a.item(-2) must return the value of filler');
+  assert.sameValue(a.item(-3), 4, 'a.item(-3) must return 4');
+  assert.sameValue(a.item(-4), 3, 'a.item(-4) must return 3');
+  assert.sameValue(a.item(-5), filler, 'a.item(-5) must return the value of filler');
+  assert.sameValue(a.item(-6), 1, 'a.item(-6) must return 1');
+});

test/built-ins/TypedArray/prototype/item/returns-undefined-for-out-of-range-index.js

@@ -0,0 +1,28 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.item
+description: >
+  Returns undefined if the specified index less than or greater than the available index range.
+info: |
+  %TypedArray%.prototype.item( index )
+
+  If k < 0 or k ≥ len, then return undefined.
+
+includes: [testTypedArray.js]
+features: [TypedArray,TypedArray.prototype.item]
+---*/
+assert.sameValue(
+  typeof TypedArray.prototype.item,
+  'function',
+  'The value of `typeof TypedArray.prototype.item` is "function"'
+);
+
+testWithTypedArrayConstructors(TA => {
+  assert.sameValue(typeof TA.prototype.item, 'function', 'The value of `typeof TA.prototype.item` is "function"');
+  let a = new TA([]);
+
+  assert.sameValue(a.item(-2), undefined, 'a.item(-2) must return undefined'); // wrap around the end
+  assert.sameValue(a.item(0), undefined, 'a.item(0) must return undefined');
+  assert.sameValue(a.item(1), undefined, 'a.item(1) must return undefined');
+});