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var BUGNUMBER = 924688;
var summary = 'Computed Property Names';
print(BUGNUMBER + ": " + summary);
// Function definitions.
function syntaxError (script) {
try {
Function(script);
} catch (e) {
if (e instanceof SyntaxError) {
return;
}
}
throw new Error('Expected syntax error: ' + script);
}
// Tests begin.
assertThrowsInstanceOf(function() { var a = {[field1]: "a", [field2]: "b"}; }, ReferenceError);
assertThrowsInstanceOf(function() {
field1 = 1;
var a = {[field1]: "a", [field2]: "b"};
}, ReferenceError);
var f1 = 1;
var f2 = 2;
var a = {[f1]: "a", [f2]: "b"};
assertEq(a[1], "a");
assertEq(a[2], "b");
var a = {[f1]: "a", f2: "b"};
assertEq(a[1], "a");
assertEq(a.f2, "b");
var a = {["f1"]: "a", [++f2]: "b"};
assertEq(a.f1, "a");
assertEq(a[3], "b");
var a = {["f1"]: "a", f2: "b"};
assertEq(a.f1, "a");
assertEq(a.f2, "b");
var i = 0;
var a = {
["foo" + ++i]: i,
["foo" + ++i]: i,
["foo" + ++i]: i
};
assertEq(a.foo1, 1);
assertEq(a.foo2, 2);
assertEq(a.foo3, 3);
var expr = "abc";
syntaxError("({[");
syntaxError("({[expr");
syntaxError("({[expr]");
syntaxError("({[expr]})");
syntaxError("({[expr] 0})");
syntaxError("({[expr], 0})");
syntaxError("[[expr]: 0]");
syntaxError("({[expr]: name: 0})");
syntaxError("({[1, 2]: 3})"); // because '1,2' is an Expression but not an AssignmentExpression
syntaxError("({[1;]: 1})"); // and not an ExpressionStatement
syntaxError("({[if (0) 0;]})"); // much less a Statement
syntaxError("function f() { {[x]: 1} }"); // that's not even an ObjectLiteral
syntaxError("function f() { [x]: 1 }"); // or that
syntaxError('a = {[f1@]: "a", [f2]: "b"}'); // unexpected symbol at end of AssignmentExpression
try { JSON.parse('{["a"]:4}'); } catch(e) {
if (!(e instanceof SyntaxError)) throw new Error('Expected syntax error');
}
// Property characteristics.
a = { ["b"] : 4 };
b = Object.getOwnPropertyDescriptor(a, "b");
assertEq(b.configurable, true);
assertEq(b.enumerable, true);
assertEq(b.writable, true);
assertEq(b.value, 4);
// Setter and getter are not hit.
Object.defineProperty(Object.prototype, "x", { set: function (x) { throw "FAIL"; },
get: function (x) { throw "FAIL"; } });
var a = {["x"]: 0};
assertEq(a.x, 0);
a = {["x"]: 1, ["x"]: 2};
assertEq(a.x, 2);
a = {x: 1, ["x"]: 2};
assertEq(a.x, 2);
a = {["x"]: 1, x: 2};
assertEq(a.x, 2);
// Symbols
var unique_sym = Symbol("1"), registered_sym = Symbol.for("2");
a = { [unique_sym] : 2, [registered_sym] : 3 };
assertEq(a[unique_sym], 2);
assertEq(a[registered_sym], 3);
// Same expression can be run several times to build objects with different property names.
a = [];
for (var i = 0; i < 3; i++) {
a[i] = {["foo" + i]: i};
}
assertEq(a[0].foo0, 0);
assertEq(a[1].foo1, 1);
assertEq(a[2].foo2, 2);
// Following are stored in object's elements rather than slots.
var i = 0;
a = { [++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i
}
for (var i = 1; i < 9; i++)
assertEq(a[i], i);
syntaxError("a.1");
syntaxError("a.2");
syntaxError("a.3");
syntaxError("a.4");
syntaxError("a.5");
syntaxError("a.6");
syntaxError("a.7");
syntaxError("a.8");
// Adding a single large index.
var i = 0;
a = { [++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[++i] : i,
[3000] : 2999
}
for (var i = 1; i < 9; i++)
assertEq(a[i], i);
assertEq(a[3000], 2999);
// Defining several properties using eval.
var code = "({";
for (i = 0; i < 1000; i++)
code += "['foo' + " + i + "]: 'ok', "
code += "['bar']: 'ok'});";
var obj = eval(code);
for (i = 0; i < 1000; i++)
assertEq(obj["foo" + i], "ok");
assertEq(obj["bar"], "ok");
// Can yield in a computed property name which is in a generator.
function* g() {
var a = { [yield 1]: 2, [yield 2]: 3};
return a;
}
var it = g();
var next = it.next();
assertEq(next.done, false);
assertEq(next.value, 1);
next = it.next("hello");
assertEq(next.done, false);
assertEq(next.value, 2);
next = it.next("world");
assertEq(next.done, true);
assertEq(next.value.hello, 2);
assertEq(next.value.world, 3);
// get and set.
expr = "abc";
syntaxError("({get [");
syntaxError("({get [expr()");
syntaxError("({get [expr]()");
syntaxError("({get [expr]()})");
syntaxError("({get [expr] 0 ()})");
syntaxError("({get [expr], 0(})");
syntaxError("[get [expr]: 0()]");
syntaxError("({get [expr](: name: 0})");
syntaxError("({get [1, 2](): 3})");
syntaxError("({get [1;](): 1})");
syntaxError("({get [if (0) 0;](){}})");
syntaxError("({set [(a)");
syntaxError("({set [expr(a)");
syntaxError("({set [expr](a){}");
syntaxError("({set [expr]}(a)");
syntaxError("({set [expr](a), 0})");
syntaxError("[set [expr](a): 0]");
syntaxError("({set [expr](a): name: 0})");
syntaxError("({set [1, 2](a) {return 3;}})");
syntaxError("({set [1;](a) {return 1}})");
syntaxError("({set [if (0) 0;](a){}})");
syntaxError("function f() { {get [x](): 1} }");
syntaxError("function f() { get [x](): 1 }");
syntaxError("function f() { {set [x](a): 1} }");
syntaxError("function f() { set [x](a): 1 }");
f1 = "abc";
syntaxError('a = {get [f1@](){}, set [f1](a){}}'); // unexpected symbol at end of AssignmentExpression
syntaxError('a = {get@ [f1](){}, set [f1](a){}}'); // unexpected symbol after get
syntaxError('a = {get [f1](){}, set@ [f1](a){}}'); // unexpected symbol after set
expr = "hey";
a = {get [expr]() { return 3; }, set[expr](v) { throw 2; }};
assertEq(a.hey, 3);
assertThrowsValue(() => { a.hey = 5; }, 2);
// Symbols with duplicate get and set.
expr = Symbol("hey");
a = {get [expr]() { return 3; }, set[expr](v) { throw 2; },
set [expr] (w) { throw 4; }, get[expr](){return 5; }};
assertEq(a[expr], 5);
assertThrowsValue(() => { a[expr] = 7; }, 4);
// expressions with side effects are called in the right order
log = "";
obj = {
"a": log += 'a',
get [log += 'b']() {},
[log += 'c']: log += 'd',
set [log += 'e'](a) {}
};
assertEq(log, "abcde");
// assignment expressions, objects and regex in computed names
obj = {
get [a = "hey"]() { return 1; },
get [a = {b : 4}.b]() { return 2; },
set [/x/.source](a) { throw 3; }
}
assertEq(obj.hey, 1);
assertEq(obj[4], 2);
assertThrowsValue(() => { obj.x = 7; }, 3);
if (typeof reportCompare === 'function')
reportCompare(0, 0, "ok");