# ng build
## Overview
`ng build` compiles the application into an output directory
### Creating a build
```bash
ng build
```
The build artifacts will be stored in the `dist/` directory.
### Build Targets and Environment Files
`ng build` can specify both a build target (`--target=production` or `--target=development`) and an
environment file to be used with that build (`--environment=dev` or `--environment=prod`).
By default, the development build target and environment are used.
The mapping used to determine which environment file is used can be found in `.angular-cli.json`:
```json
"environmentSource": "environments/environment.ts",
"environments": {
"dev": "environments/environment.ts",
"prod": "environments/environment.prod.ts"
}
```
These options also apply to the serve command. If you do not pass a value for `environment`,
it will default to `dev` for `development` and `prod` for `production`.
```bash
# these are equivalent
ng build --target=production --environment=prod
ng build --prod --env=prod
ng build --prod
# and so are these
ng build --target=development --environment=dev
ng build --dev --e=dev
ng build --dev
ng build
```
You can also add your own env files other than `dev` and `prod` by doing the following:
- create a `src/environments/environment.NAME.ts`
- add `{ "NAME": 'src/environments/environment.NAME.ts' }` to the `apps[0].environments` object in `.angular-cli.json`
- use them via the `--env=NAME` flag on the build/serve commands.
### Base tag handling in index.html
When building you can modify base tag (``) in your index.html with `--base-href your-url` option.
```bash
# Sets base tag href to /myUrl/ in your index.html
ng build --base-href /myUrl/
ng build --bh /myUrl/
```
### Bundling
All builds make use of bundling, and using the `--prod` flag in `ng build --prod`
or `ng serve --prod` will also make use of uglifying and tree-shaking functionality.
## Options
aot
`--aot` _default: false_
Build using Ahead of Time compilation.
app
`--app` (aliases: `-a`)
Specifies app name or index to use.
base-href
`--base-href` (aliases: `-bh`)
Base url for the application being built.
deploy-url
`--deploy-url` (aliases: `-d`)
URL where files will be deployed.
output-path
`--output-path` (aliases: `-op`)
Path where output will be placed
environment
`--environment` (aliases: `-e`)
Defines the build environment.
extract-css
`--extract-css` (aliases: `-ec`)
Extract css from global styles onto css files instead of js ones.
i18n-file
`--i18n-file`
Localization file to use for i18n.
i18n-format
`--i18n-format`
Format of the localization file specified with --i18n-file.
locale
`--locale`
Locale to use for i18n.
output-hashing
`--output-hashing` (aliases: `-oh`)
Define the output filename cache-busting hashing mode.
Values: `none`, `all`, `media`, `bundles`
output-path
`--output-path` (aliases: `-op`)
Path where output will be placed.
poll
`--poll`
Enable and define the file watching poll time period (milliseconds).
progress
`--progress` (aliases: `-pr`) _default value: true_
Log progress to the console while building.
sourcemap
`--sourcemap` (aliases: `-sm`, `sourcemaps`)
Output sourcemaps.
stats-json
`--stats-json` (aliases: `-`)
Generates a `stats.json` file which can be analyzed using tools such as: `webpack-bundle-analyzer` or https://webpack.github.io/analyse.
target
`--target` (aliases: `-t`, `-dev`, `-prod`) _default value: development_
Defines the build target.
vendor-chunk
`--vendor-chunk` (aliases: `-vc`) _default value: true_
Use a separate bundle containing only vendor libraries.
verbose
`--verbose` (aliases: `-v`) _default value: false_
Adds more details to output logging.
watch
`--watch` (aliases: `-w`)
Run build when files change.