Cannot find module ‘underscore’ || install underscore module in angular 2

You need to install that libraries typings definitions in previous versions, if you want to use an JS library in TypeScript.

In newer version of TypeScript uses @types system. So now you don't need to install typings manually, you can just write this. For first install

npm install -g typescript@next

1 2	npm install -g typescript@next

And then

npm install --save underscore
npm install --save @types/underscore

1 2	npm install --save underscore npm install --save @types/underscore

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