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babel.js
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babel.js
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import { createRequire } from "module";
const require = createRequire(import.meta.url);
// Basic smoke tests for @babel/standalone
(process.env.TEST_TYPE === "cov" ? describe.skip : describe)(
"@babel/standalone",
() => {
let Babel;
beforeAll(() => {
Babel = require("../babel.js");
});
it("handles the es2015-no-commonjs preset", () => {
const output = Babel.transform('const getMessage = () => "Hello World"', {
presets: ["es2015-no-commonjs"],
}).code;
expect(output).toBe(
"var getMessage = function getMessage() {\n" +
' return "Hello World";\n' +
"};",
);
});
it("handles the es2015-loose preset", () => {
const output = Babel.transform("class A {}", {
sourceType: "script",
presets: ["es2015-loose"],
}).code;
expect(output).toBe('var A = function A() {\n "use strict";\n};');
});
it("handles the typescript preset", () => {
const output = Babel.transform("var a: string;", {
presets: [["typescript", { allExtensions: true }]],
}).code;
expect(output).toBe("var a;");
});
it("handles the flow preset", () => {
const output = Babel.transform("var a: string;", {
presets: ["flow"],
}).code;
expect(output).toBe("var a;");
});
it("can translate simple ast", () => {
const ast = {
type: "Program",
start: 0,
end: 2,
directives: [],
body: [
{
type: "ExpressionStatement",
start: 0,
end: 1,
expression: {
type: "NumericLiteral",
start: 0,
end: 2,
value: 42,
raw: "42",
},
},
],
sourceType: "script",
};
const output = Babel.transformFromAst(ast, "42", {
presets: ["es2015"],
}).code;
expect(output).toBe("42;");
});
it("handles the react preset", () => {
const output = Babel.transform(
"const someDiv = <div>{getMessage()}</div>",
{
presets: [["react", { runtime: "classic" }]],
},
).code;
expect(output).toBe(
'const someDiv = /*#__PURE__*/React.createElement("div", null, getMessage());',
);
});
it("handles presets with options", () => {
const output = Babel.transform("export let x", {
presets: [["es2015", { modules: false }]],
}).code;
expect(output).toBe("export var x;");
});
it("handles specifying a plugin by name", () => {
const output = Babel.transform('const getMessage = () => "Hello World"', {
plugins: ["transform-arrow-functions"],
}).code;
// Transforms arrow syntax but NOT "const".
expect(output).toBe(
"const getMessage = function () {\n" +
' return "Hello World";\n' +
"};",
);
});
it("handles plugins with options", () => {
const output = Babel.transform("`${x}`", {
plugins: [["transform-template-literals", { loose: true }]],
}).code;
expect(output).toBe('"" + x;');
});
it("throws on invalid preset name", () => {
expect(() =>
Babel.transform("var foo", { presets: ["lolfail"] }),
).toThrow(/Invalid preset specified in Babel options: "lolfail"/);
});
it("throws on invalid plugin name", () => {
expect(() =>
Babel.transform("var foo", { plugins: ["lolfail"] }),
).toThrow(/Invalid plugin specified in Babel options: "lolfail"/);
});
describe("env preset", () => {
it("works w/o targets", () => {
const output = Babel.transform("const a = 1;", {
sourceType: "script",
presets: [["env", { targets: { browsers: "ie 6" } }]],
}).code;
expect(output).toBe("var a = 1;");
});
it("doesn't transpile `const` with chrome 60", () => {
const output = Babel.transform("const a = 1;", {
sourceType: "script",
presets: [
[
"env",
{
targets: {
chrome: 60,
},
},
],
],
}).code;
expect(output).toBe("const a = 1;");
});
it("transpiles `const` with chrome 60 and preset-es2015", () => {
const output = Babel.transform("const a = 1;", {
sourceType: "script",
presets: [
[
"env",
{
targets: {
chrome: 60,
},
},
],
"es2015",
],
}).code;
expect(output).toBe("var a = 1;");
});
it("uses transform-new-targets plugin", () => {
const output = Babel.transform("function Foo() {new.target}", {
sourceType: "script",
presets: [["env", { targets: { browsers: "ie 6" } }]],
}).code;
expect(output).toBe(
"function Foo() {\n this instanceof Foo ? this.constructor : void 0;\n}",
);
});
it("useBuiltIns works", () => {
const output = Babel.transform("[].includes(2)", {
sourceType: "module",
targets: { ie: 11 },
presets: [
["env", { useBuiltIns: "usage", corejs: 3, modules: false }],
],
}).code;
expect(output).toMatchInlineSnapshot(`
"import \\"core-js/modules/es.array.includes.js\\";
[].includes(2);"
`);
});
it("regenerator works", () => {
const output = Babel.transform("function* fn() {}", {
sourceType: "module",
targets: { ie: 11 },
presets: ["env"],
}).code;
expect(output).toMatch("regeneratorRuntime.mark(fn)");
});
});
describe("custom plugins and presets", () => {
const lolizer = () => ({
visitor: {
Identifier(path) {
path.node.name = "LOL";
},
},
});
it("allows custom plugins to be registered", () => {
Babel.registerPlugin("lolizer", lolizer);
const output = Babel.transform(
"function helloWorld() { alert(hello); }",
{ plugins: ["lolizer"] },
);
expect(output.code).toBe(`function LOL() {
LOL(LOL);
}`);
});
it("allows custom presets to be registered", () => {
Babel.registerPreset("lulz", { plugins: [lolizer] });
const output = Babel.transform(
"function helloWorld() { alert(hello); }",
{ presets: ["lulz"] },
);
expect(output.code).toBe(`function LOL() {
LOL(LOL);
}`);
});
});
describe("regressions", () => {
it("#11534 - supports quantifiers in unicode regexps", () => {
expect(() =>
Babel.transform("/a*/u", { presets: ["es2015"] }),
).not.toThrow();
});
it("#11628 - supports stage-0 passing importAssertionsVersion to stage-1", () => {
expect(() =>
Babel.transform("const getMessage = () => 'Hello World'", {
presets: [["stage-0", { decoratorsBeforeExport: false }]],
}),
).not.toThrow();
});
it("#11897 - [...map.keys()] in Babel source should be transformed correctly", () => {
expect(() =>
Babel.transform("for (let el of []) { s => el }", {
plugins: ["transform-block-scoping"],
}),
).not.toThrow();
});
it("#12815 - unicode property letter short alias should be transformed", () => {
expect(() =>
Babel.transform("/\\p{L}/u", {
plugins: ["proposal-unicode-property-regex"],
}),
).not.toThrow();
});
it("#14425 - numeric separators should be parsed correctly", () => {
expect(() => Babel.transform("1_1", {})).not.toThrow();
});
});
},
);