ES6 + 자바 스크립트 모듈 내보내기 옵션

ES6 + 자바 스크립트 모듈 내보내기 옵션

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ES6 모듈의 공개 내보내기가 다음 두 가지 방법으로 수행되는 것을 보았습니다.

// method 1
export var getAnswer = function () { return 'forty two'; };

// method 2
export default function () { return 'forty two'; };

1. 둘 다 유효합니까?
2. 그렇다면 둘 다 존재하는 이유는 무엇입니까?
3. ES6 구문을 사용하는 모듈 내보내기에 대한 다른 유효한 옵션이 있습니까?

내 googlefu로 답을 찾지 못한 것이 놀랍습니다. CommonJS, RequireJS, AMD, Node 등이 아닌 ES6 모듈 에만 관심이 있습니다 .

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1 년 후, 주제에 대해 내가 찾은 최고의 정보가 여기 있습니다.

수출에는 4 가지 유형이 있습니다. 다음은이를 사용하는 일부 가져 오기와 함께 각각의 사용 예입니다.

내보내기 구문

// default exports
export default 42;
export default {};
export default [];
export default (1 + 2);
export default foo;
export default function () {}
export default class {}
export default function foo () {}
export default class foo {}

// variables exports
export var foo = 1;
export var foo = function () {};
export var bar;
export let foo = 2;
export let bar;
export const foo = 3;
export function foo () {}
export class foo {}

// named exports
export {};
export {foo};
export {foo, bar};
export {foo as bar};
export {foo as default};
export {foo as default, bar};

// exports from
export * from "foo";
export {} from "foo";
export {foo} from "foo";
export {foo, bar} from "foo";
export {foo as bar} from "foo";
export {foo as default} from "foo";
export {foo as default, bar} from "foo";
export {default} from "foo";
export {default as foo} from "foo";

가져 오기 구문

// default imports
import foo from "foo";
import {default as foo} from "foo";

// named imports
import {} from "foo";
import {bar} from "foo";
import {bar, baz} from "foo";
import {bar as baz} from "foo";
import {bar as baz, xyz} from "foo";

// glob imports
import * as foo from "foo";

// mixing imports
import foo, {baz as xyz} from "foo";
import foo, * as bar from "foo";

// just import
import "foo";

출처.

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둘 다 유효합니다.

Method 1 provides named exports. The key here is that you can export more than one thing. This should be used instead of exporting an object with multiple properties. When you import a module with named exports, use import {a, b} from c.

Method 2 provides the default export. There can be only one default export. This is primarily used when you are exporting a single thing, like a class, or a single function that you expect to be used without any additional support. When you import a module with a default export, use import d from c.

Note that you can use both! so if you have a major, primary function with a handful of occasionally used helpers, you can export the helpers, and export default the primary. When you import a module and need both kinds of exports, use import d, {a, b} from c.

One other option is that you can get named exports by listing them at the end of your module, like so: export {a,b,c}. You can also rename them export {a as $a, b as c}.

I got all of this from this article, which is the best source for up-to-date es6 module information that I've been able to find.

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1. Are both of these valid?

No, export function () { return answer; }; is invalid, either you use default, or you add a name to that function declaration.

2. If so, why do they both exist?

They don't :)

3. Are there other valid options for module exports using ES6 syntax?

You can see a lot of valid options here: https://github.com/eslint/espree/pull/43

참고URL : https://stackoverflow.com/questions/25494365/es6-javascript-module-export-options