import-defer-syntax.js

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// |jit-test| skip-if: getBuildConfiguration("release_or_beta"); --enable-defer-import-eval

load(libdir + "asserts.js");

const ast = Reflect.parse("import defer * as ns from './module.js'", {target: "module"});

assertEq(ast.type, "Program");

assertEq(ast.body.length, 1);

const importDecl = ast.body[0];

assertEq(importDecl.type, "ImportDeclaration");

assertEq(importDecl.phase, "defer");

assertEq(importDecl.specifiers.length, 1);

const spec = importDecl.specifiers[0];

assertEq(spec.type, "ImportNamespaceSpecifier");

assertEq(spec.name.type, "Identifier");

assertEq(spec.name.name, "ns");

const moduleRequest = importDecl.moduleRequest;

assertEq(moduleRequest.type, "ModuleRequest");

assertEq(moduleRequest.source.type, "Literal");

assertEq(moduleRequest.source.value, "./module.js");

assertEq(moduleRequest.attributes.length, 0);

// Import attributes are allowed on `import defer` declarations.

const astWithAttributes = Reflect.parse(

  "import defer * as ns from './module.js' with { type: 'json' }", {target: "module"});

assertEq(astWithAttributes.body[0].phase, "defer");

const attributes = astWithAttributes.body[0].moduleRequest.attributes;

assertEq(attributes.length, 1);

assertEq(attributes[0].type, "ImportAttribute");

assertEq(attributes[0].key.name, "type");

assertEq(attributes[0].value.value, "json");

// Error outside of module context

assertThrowsInstanceOf(() => Reflect.parse("import defer * as ns from './module.js'"), SyntaxError);

// `import defer` requires a namespace import.

assertThrowsInstanceOf(() => Reflect.parse("import defer mod from './module.js'", {target: "module"}), SyntaxError);

assertThrowsInstanceOf(() => Reflect.parse("import defer { mod } from './module.js'", {target: "module"}), SyntaxError);

assertThrowsInstanceOf(() => Reflect.parse("import defaultBinding, defer * as ns from './module.js'", {target: "module"}), SyntaxError);

// `defer` is a contextual keyword: without a following `*` it is just a

// regular default binding name, like `import source from '...'` in

// import-source-syntax.js.

const plainAst = Reflect.parse("import defer from './module.js'", {target: "module"});

const plainDecl = plainAst.body[0];

// Without a following `*`, this is an ordinary evaluation-phase import, not a

// deferred one.

assertEq(plainDecl.phase, "evaluation");

const plainSpec = plainDecl.specifiers[0];

assertEq(plainSpec.type, "ImportSpecifier");

assertEq(plainSpec.id.name, "default");

assertEq(plainSpec.name.name, "defer");