[TypeScript] Using Lodash in TypeScript with Typings and SystemJS

One of the most confusing parts of getting started with TypeScript is figuring out how to use all the libraries that you know and love from JavaScript. This lesson walks you through including Lodash in your project, installing Lodash definition files, and then properly loading Lodash with SystemJS.

install:

npm install -g typings

Excludes extra files and folder:

{
    "compilerOptions": {
        "rootDir": "src",
        "module": "commonjs",
        "target": "es5",
        "noImplicitAny": false,
        "sourceMap": false,
        "outDir": "./dist",
        "noEmitOnError": true
    },
    "exclude": [
        "node_modules",
        "typings/main",
        "typings/main.d.ts"
    ]
}

Install lodash:

typing install lodash --save

Import lodash:

import * as _ from 'lodash';

This time, Compiler will report error says that cannot find lodash. This is because we need to tell System.js where to find lodash.

<script>
    System.config({
        packages: {
            "dist": {
                "defaultExtension": "js",
                "main": "main"
            }
        },
        map: {
            "lodash": "https://npmcdn.com/lodash@4.13.1"
        }
    });

    System.import("dist")
</script>

Use it:

import {SocialNetwork} from './interfaces';
import * as _ from 'lodash';

class App implements SocialNetwork{
    title = "Facebook";

    getPeople(){
        return [{name: 'John'}]
    }
}

console.log(_.isArray(new App().getPeople()));