Typescript shows error when importing something

Question

Why does it show error when using import ?

Answer 1

您尚未在文件中导入 lodash：

import _ from 'lodash';

Answer 2

but i don't want to import loadash, I will include it in my html page.

if you've already imported "lodash" in html page, you can use the declare keyword in your typescript source like this:

declare var _: any;

_.map([1, 2, 3], function(el: number, index: number) {
// ...
});

The declare keyword is used for ambient declarations where you want to define a variable that may not have originated from a TypeScript file.

-- EDIT --

After a search , I found "lodash" type definition is available at: https://www.npmjs.com/package/@types/lodash