Lodash in angular2, declare var_:any not working

问题

I am using lodash in my angular2 app. by using declare var _: any; i am doing lodash operation such as _.findIndex(...) . Now i am facing one issue. sometimes while loading page i am getting error as below

EXCEPTION: ReferenceError: _ is not defined

how to avoid this? As my assumption, lodash code is executed before declare var _: any;

回答1:

In fact, it depends on the way to configure / include the lodash library into your HTML page:

Include the lodash.js file into a script element. This way, lodash is available as a global variable (_) into the application. In this case, you need to define it leveraging ambient declarations of TypeScript:
```
declare var _: any;
```
Configure the lodash.js file into the SystemJS configuration. In this way, the lodash library will detect that it will be used within a module loader so it will register itself as a module and return the _ variable into exports. In this case, you need to use an import to get it. Since the _ variable is directly set into exports, you need to import it this way:
```
import _ from 'lodash';
```
The corresponding configuration would be:
```
System.config({
  (...)
  map: {
    lodash: 'node_modules/lodash/lodash.js'
  },
  meta: {
    lodash: { format: 'amd' }
  }
});
```

回答2:

If you are using TypeScript, then you need to import the library in your file:

import _ from 'lodash';

Have a look at a simular question: angular2 failing lodash import

来源：https://stackoverflow.com/questions/36171727/lodash-in-angular2-declare-var-any-not-working

标签

angular

lodash