# Installation

To install prebuilt Electron binaries, use [`npm`][npm].
The preferred method is to install Electron as a development dependency in your
app:

```sh
npm install electron --save-dev
```

See the [Electron versioning doc][versioning] for info on how to
manage Electron versions in your apps.

## Global Installation

You can also install the `electron` command globally in your `$PATH`:

```sh
npm install electron -g
```

## Customization

If you want to change the architecture that is downloaded (e.g., `ia32` on an
`x64` machine), you can use the `--arch` flag with npm install or set the
`npm_config_arch` environment variable:

```shell
npm install --arch=ia32 electron
```

In addition to changing the architecture, you can also specify the platform
(e.g., `win32`, `linux`, etc.) using the `--platform` flag:

```shell
npm install --platform=win32 electron
```

## Proxies

If you need to use an HTTP proxy you can [set these environment variables][proxy-env].

## Custom Mirrors and Caches
During installation, the `electron` module will call out to
[`electron-download`][electron-download] to download prebuilt binaries of
Electron for your platform. It will do so by contacting GitHub's
release download page (`https://github.com/electron/electron/releases/tag/v$VERSION`,
where `$VERSION` is the exact version of Electron).

If you are unable to access GitHub or you need to provide a custom build, you
can do so by either providing a mirror or an existing cache directory.

#### Mirror
You can use environment variables to override the base URL, the path at which to
look for Electron binaries, and the binary filename. The url used by `electron-download`
is composed as follows:

```txt
url = ELECTRON_MIRROR + ELECTRON_CUSTOM_DIR + '/' + ELECTRON_CUSTOM_FILENAME
```

For instance, to use the China mirror:

```txt
ELECTRON_MIRROR="https://npm.taobao.org/mirrors/electron/"
```

#### Cache
Alternatively, you can override the local cache. `electron-download` will cache
downloaded binaries in a local directory to not stress your network. You can use
that cache folder to provide custom builds of Electron or to avoid making contact
with the network at all.

* Linux: `$XDG_CACHE_HOME` or `~/.cache/electron/`
* MacOS: `~/Library/Caches/electron/`
* Windows: `$LOCALAPPDATA/electron/Cache` or `~/AppData/Local/electron/Cache/`

On environments that have been using older versions of Electron, you might find the
cache also in `~/.electron`.

You can also override the local cache location by providing a `ELECTRON_CACHE`
environment variable.

The cache contains the version's official zip file as well as a checksum, stored as
a text file. A typical cache might look like this:

```sh
├── electron-v1.7.9-darwin-x64.zip
├── electron-v1.8.1-darwin-x64.zip
├── electron-v1.8.2-beta.1-darwin-x64.zip
├── electron-v1.8.2-beta.2-darwin-x64.zip
├── electron-v1.8.2-beta.3-darwin-x64.zip
├── SHASUMS256.txt-1.7.9
├── SHASUMS256.txt-1.8.1
├── SHASUMS256.txt-1.8.2-beta.1
├── SHASUMS256.txt-1.8.2-beta.2
├── SHASUMS256.txt-1.8.2-beta.3
```

## Skip binary download
When installing the `electron` NPM package, it automatically downloads the electron binary.

This can sometimes be unnecessary, e.g. in a CI environment, when testing another component.

To prevent the binary from being downloaded when you install all npm dependencies you can set the environment variable `ELECTRON_SKIP_BINARY_DOWNLOAD`.
E.g.:
```sh
ELECTRON_SKIP_BINARY_DOWNLOAD=1 npm install
```

## Troubleshooting

When running `npm install electron`, some users occasionally encounter
installation errors.

In almost all cases, these errors are the result of network problems and not
actual issues with the `electron` npm package. Errors like `ELIFECYCLE`,
`EAI_AGAIN`, `ECONNRESET`, and `ETIMEDOUT` are all indications of such
network problems. The best resolution is to try switching networks, or
wait a bit and try installing again.

You can also attempt to download Electron directly from
[electron/electron/releases][releases]
if installing via `npm` is failing.

If installation fails with an `EACCESS` error you may need to
[fix your npm permissions][npm-permissions].

If the above error persists, the [unsafe-perm][unsafe-perm] flag may need to be
set to true:

```sh
sudo npm install electron --unsafe-perm=true
```

On slower networks, it may be advisable to use the `--verbose` flag in order to
show download progress:

```sh
npm install --verbose electron
```

If you need to force a re-download of the asset and the SHASUM file set the
`force_no_cache` environment variable to `true`.

[npm]: https://docs.npmjs.com
[versioning]: ./electron-versioning.md
[releases]: https://github.com/electron/electron/releases
[proxy-env]: https://github.com/request/request/tree/f0c4ec061141051988d1216c24936ad2e7d5c45d#controlling-proxy-behaviour-using-environment-variables
[electron-download]: https://github.com/electron-userland/electron-download
[npm-permissions]: https://docs.npmjs.com/getting-started/fixing-npm-permissions
[unsafe-perm]: https://docs.npmjs.com/misc/config#unsafe-perm
