How does NPM handle version conflicts?

Since NPM version 3 node modules and dependencies are all installed at the same root level. But what if I install two modules that depend on two different versions of the same module? For instance, if I install async `npm i [email protected]`, which [requires lodash version 4.14.0][1], then I install yeoman `npm i [email protected]`, which [requires lodash version version 3.2.0][2], how does npm resolve this conflict?


[1]:

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[2]:

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All the dependencies and the internal dependencies tries to get a place in the root of the `node_modules` unless there is a conflict with the same dependency, but different version. **When a conflict raises, it creates a sub `node_modules` under each dependency needed** and pushes conflicting internal libraries in it.

EXAMPLE:
Here, "A" internally depends on "[email protected]" and "B" depends on "[email protected]".
When you execute install A and B like below:

```
npm install A
npm install B

node_modules
|_ A
|_ alpha @v1.0
|_ B
| |_ node_modules
| |_ alpha @v2.0
|_ ...
```

NOTE: Another `node_modules` created under "B" inside the main node_module.

For more details: [visit this post][1].


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