arc-resolver

API

$3

``js
import Resolver from 'arc-resolver';
`

- fs (_optional_): a filesystem that conforms to the node.js fs api. Defaults to the built-in fs module

#### Instance methods

- clearCache()
- getMatchesSync(path)
- getDirMatchesSync(dir, request)
- resolveSync(path, flags)
- isAdaptiveSync(path)

$3

`js
import { MatchSet } from 'arc-resolver';
`

- matches (_required_): an Array of Objects with the keys flags and value:
- flags: an Array of strings representing the required flags for the value
- value: any value to associate with the flags

#### Properties

- count: the number of possible matches
- default: the default value (the least specific, the one with no flags)

#### Methods

- match(flags): return the matching value for a flagset
- flags: an Object where each key represents a flag and the value is a boolean indicating whether that flag is active

Defining flags

arc adapts files based on a filenaming convension:

`webidl
style.css
style[android].css
`

$3

Write your application as though the flagged version of the file did not exist:

`css
@import url('./style.css');
`

When bundling the css (using arc-webpack or arc-lasso), if the android flag is set, style[android].css will replace style.css in the output bundle.

$3

#### Require all flags (AND)

Use the plus (+) to specify that all of the listed flags need to match:

`webidl
style[mobile+android].css
`

#### Require any flag (OR)

Use the comma (,) to specify that one of the listed flags needs to match:

`webidl
style[android,ios].css
`

#### Combining flag logic

The plus (+) has higher precedence than the comma (,), similar to how && has higher precedence than || in JavaScript.

For example,

`webidl
style[mobile+ios,mobile+android].css
`

Is logically equivalent to:

`js
(mobile && ios) || (mobile && android)
`

##### Subgroups of flags

To increase the precedence of a group, you can wrap it in []:

`webidl
style[mobile+[ios,android]].css
`

This is logically equivalent to the previous example.

$3

> More Flags === Higher Specificity

Given the following files:

`webidl
style.css
style[mobile,tablet,headset,desktop].css
style[mobile+[ios,android]].css
style[mobile+ios+chrome,safari].css
`

The matching logic looks something like:

`coffee
if mobile & ios & chrome
'style[mobile+ios+chrome,safari].css'

else if mobile & ios
'style[mobile+[ios,android]].css'

else if mobile & android
'style[mobile+[ios,android]].css'

else if safari
'style[mobile+ios+chrome,safari].css'

else if mobile
'style[mobile,tablet,headset,desktop].css'

else if tablet
'style[mobile,tablet,headset,desktop].css'

else if headset
'style[mobile,tablet,headset,desktop].css'

else if desktop
'style[mobile,tablet,headset,desktop].css'

else
'style.css'
``