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// Copyright 2019 Google, Inc. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: prod-OptionalExpression
description: >
optional chain on member expression
info: |
Left-Hand-Side Expressions
OptionalExpression:
MemberExpression OptionalChain
features: [optional-chaining]
---*/
// PrimaryExpression
// IdentifierReference
const a = {b: 22};
assert.sameValue(22, a?.b);
// this
function fn () {
return this?.a
}
assert.sameValue(33, fn.call({a: 33}));
// Literal
assert.sameValue(undefined, "hello"?.a);
assert.sameValue(undefined, null?.a);
// ArrayLiteral
assert.sameValue(2, [1, 2]?.[1]);
// ObjectLiteral
assert.sameValue(44, {a: 44}?.a);
// FunctionExpression
assert.sameValue('a', (function a () {}?.name));
// ClassExpression
assert.sameValue('Foo', (class Foo {}?.name));
// GeneratorFunction
assert.sameValue('a', (function * a () {}?.name));
// AsyncFunctionExpression
// assert.sameValue('a', (async function a () {}?.name)); // Not available in ES7
// AsyncGeneratorExpression
// assert.sameValue('a', (async function * a () {}?.name)); // Not available in ES7
// RegularExpressionLiteral
assert.sameValue(true, /[a-z]/?.test('a'));
// TemplateLiteral
assert.sameValue('h', `hello`?.[0]);
// CoverParenthesizedExpressionAndArrowParameterList
assert.sameValue(undefined, ({a: 33}, null)?.a);
assert.sameValue(33, (undefined, {a: 33})?.a);
// MemberExpression [ Expression ]
const arr = [{a: 33}];
assert.sameValue(33, arr[0]?.a);
assert.sameValue(undefined, arr[1]?.a);
// MemberExpression .IdentifierName
const obj = {a: {b: 44}};
assert.sameValue(44, obj.a?.b);
assert.sameValue(undefined, obj.c?.b);
// MemberExpression TemplateLiteral
function f2 () {
return {a: 33};
}
function f3 () {}
assert.sameValue(33, f2`hello world`?.a);
assert.sameValue(undefined, f3`hello world`?.a);
// MemberExpression SuperProperty
class A {
a () {}
undf () {
return super.a?.c;
}
}
class B extends A {
dot () {
return super.a?.name;
}
expr () {
return super['a']?.name;
}
undf2 () {
return super.b?.c;
}
}
const subcls = new B();
assert.sameValue('a', subcls.dot());
assert.sameValue('a', subcls.expr());
assert.sameValue(undefined, subcls.undf2());
assert.sameValue(undefined, (new A()).undf());
// MemberExpression MetaProperty
class C {
constructor () {
assert.sameValue(undefined, new.target?.a);
}
}
new C();
// new MemberExpression Arguments
class D {
constructor (val) {
this.a = val;
}
}
assert.sameValue(99, new D(99)?.a);
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