"use strict"; var { ObjectUtils } = ChromeUtils.import( "resource://gre/modules/ObjectUtils.jsm" ); var { PromiseTestUtils } = ChromeUtils.import( "resource://testing-common/PromiseTestUtils.jsm" ); add_task(async function test_strict() { let loose = { a: 1 }; let strict = ObjectUtils.strict(loose); loose.a; // Should not throw. loose.b || undefined; // Should not throw. strict.a; // Should not throw. PromiseTestUtils.expectUncaughtRejection(/No such property: "b"/); Assert.throws(() => strict.b, /No such property: "b"/); "b" in strict; // Should not throw. strict.b = 2; strict.b; // Should not throw. PromiseTestUtils.expectUncaughtRejection(/No such property: "c"/); Assert.throws(() => strict.c, /No such property: "c"/); "c" in strict; // Should not throw. loose.c = 3; strict.c; // Should not throw. });