ES6：如何在库的多个文件中重用 const 变量而不将其暴露给客户端代码？

Question

我正在编写一个由多个文件组成的库：

./lib:
 - core.js
 - file1.js
 - file2.js
 - file3.js

lib/core.js 包含我需要在 file1.js、file2.js 和 file3.js.

中重用的公共变量

例如，core.js：


/**
 * I would like to reuse this constant in file1.js, file2.js and file3.js,
 * but I don't want client code to be able to access the value of this constant
 * when importing components of my library, like "aFunction" below.
 */
export const CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY = 'Some value';

/**
 * I would like to expose this function to client code
 * as well as to the other files of the library (file1.js, file2.js and file3.js).
 */
export const aFunction = () => {
}

...

然后file1.js（file2.js和file3.js类似）：

import { CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY } from './core'

/**
 * This function should be available to the client code (as "aFunction" of core.js),
 * but CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY should not.
 */
export const file1Function = () => {
    // Need to use `CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY` here
    console.log(CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY)
}

如何使用 ES6 模块实现此目的？现在，通过此设置，CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY 也可用于客户端代码。

但我想保留它 "module-private"，即仅适用于我的库代码。

感谢关注

Answer 1

如果您不希望任何变量在您的模块（文件）外可见，那么只需声明它并在您的模块内分配一个值，但不要导出 variable.In 您的 core.js：

const CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY = 'Some value';

export const getThatVariable = () => CONSTANT_I_WANT_TO_REUSE_IN_OTHER_FILES_OF_THE_LIBRARY;

export const aFunction = () => {
}

在你的file1.js中：

import { getThatVariable } from "./core.js"


export const file1Function = () => {
    const neededVariable = getThatVariable();
    console.log(neededVariable);
}

ES6：如何在库的多个文件中重用 const 变量而不将其暴露给客户端代码？

ES6: How to reuse a const variable in multiple files of the library BUT WITHOUT exposing it to client code?

javascript

ecmascript-6

es6-modules