我们什么时候使用 typescript import * as？

Question

Trying to developer a mental model for what import * as Blah does. For example:

import * as StackTrace from 'stacktrace-js';

How does that work and when do we do import * ?

Answer 1

Not really an answer, but a usage: Consider you have a few constant strings to be used in your application, you can define them in a single file and export

export const name = "NAME";
export const someOtherString = "SOME_CONST_STRING";

Then you can import them in a single variable using:

import * as CONST_STRINGS from './yourFilePath';

and use as

CONST_STRINGS.name 
CONST_STRINGS.someOtherString

Answer 2

From the TypeScript doc :

Import the entire module into a single variable, and use it to access the module exports

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The example code imports all exports of the stacktrace-js module into a variable called StackTrace .

Any named exports will be available as properties of the same name.

If the module has a default export it will be available as the default property.

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Note also from the TypeScript Module doc :

Starting with ECMAScript 2015, JavaScript has a concept of modules. TypeScript shares this concept.

So TypeScript modules behave in the same way as ES6 JavaScript modules.

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You would use import * as in either TypeScript or JavaScript when you want access to all of the module exports in a single variable.