# Class UrlRules

API for managing URL rules

This API is used to create and manage URL rules. URL rules are a mechanism to respond to specific URL patterns.

The most commonly used methods are [[otherwise]] and [[when]].

This API is found at `$urlService.rules` (see: [[UIRouter.urlService]], [[URLService.rules]])

- Defined in src/router/url/url-rules.js:72

##### Index

### Constructors

constructor

### Properties

_id
_otherwiseFn
_rules
_sorted
_sortFn
urlRuleFactory

### Methods

ensureSorted
initial
otherwise
removeRule
rule
rules
sort
stableSort
when

## Constructors

### constructor

- new UrlRules(urlRuleFactory: any): UrlRules

  #### Parameters

  - urlRuleFactory: any

  #### Returns UrlRules

  - Defined in src/router/url/url-rules.js:73

## Properties

### _id

_id: number

- Defined in src/router/url/url-rules.js:76

### _otherwiseFn

_otherwiseFn: any

- Defined in src/router/url/url-rules.js:167

### _rules

_rules: any[]

- Defined in src/router/url/url-rules.js:75
- Defined in src/router/url/url-rules.js:265

### _sorted

_sorted: boolean

- Defined in src/router/url/url-rules.js:168
- Defined in src/router/url/url-rules.js:195
- Defined in src/router/url/url-rules.js:266

### _sortFn

_sortFn: any

- Defined in src/router/url/url-rules.js:74
- Defined in src/router/url/url-rules.js:252

### urlRuleFactory

urlRuleFactory: any

- Defined in src/router/url/url-rules.js:77

## Methods

### ensureSorted

- ensureSorted(): void

  #### Returns void

  - Defined in src/router/url/url-rules.js:269

### initial

- initial(handler: any): void

  Defines the initial state, path, or behavior to use when the app starts.

  This rule defines the initial/starting state for the application.

  This rule is triggered the first time the URL is checked (when the app initially loads). The rule is triggered only when the url matches either `""` or `"/"`.

  Note: The rule is intended to be used when the root of the application is directly linked to. When the URL is not `""` or `"/"` and doesn't match other rules, the [[otherwise]] rule is triggered. This allows 404-like behavior when an unknown URL is deep-linked.

  #### Example:

  Start app at `home` state.

      .initial({ state: 'home' });

  #### Example:

  Start app at `/home` (by url)

      .initial('/home');

  #### Example:

  When no other url rule matches, go to `home` state

      .initial((matchValue, url, router) => {
        console.log('initial state');
        return { state: 'home' };
      })

  #### Parameters

  - handler: any

    The initial state or url path, or a function which returns the state or url path (or performs custom logic).

  #### Returns void

  - Defined in src/router/url/url-rules.js:115

### otherwise

- otherwise(handler: any): void

  Defines the state, url, or behavior to use when no other rule matches the URL.

  This rule is matched when no other rule matches. It is generally used to handle unknown URLs (similar to "404" behavior, but on the client side).

  - If `handler` a string, it is treated as a url redirect

  #### Example:

  When no other url rule matches, redirect to `/index`

      .otherwise('/index');

  - If `handler` is an object with a `state` property, the state is activated.

  #### Example:

  When no other url rule matches, redirect to `home` and provide a `dashboard` parameter value.

      .otherwise({ state: 'home', params: { dashboard: 'default' } });

  - If `handler` is a function, the function receives the current url ([[UrlParts]]) and the [[UIRouter]] object. The function can perform actions, and/or return a value.

  #### Example:

  When no other url rule matches, manually trigger a transition to the `home` state

      .otherwise((matchValue, urlParts, router) => {
        router.stateService.go('home');
      });

  #### Example:

  When no other url rule matches, go to `home` state

      .otherwise((matchValue, urlParts, router) => {
        return { state: 'home' };
      });

  #### Parameters

  - handler: any

    The url path to redirect to, or a function which returns the url path (or performs custom logic).

  #### Returns void

  - Defined in src/router/url/url-rules.js:165

### removeRule

- removeRule(rule: any): void

  Remove a rule previously registered

  #### Parameters

  - rule: any

    the matcher rule that was previously registered using [[rule]]

  #### Returns void

  - Defined in src/router/url/url-rules.js:175

### rule

- rule(rule: any): () => void

  Manually adds a URL Rule.

  Usually, a url rule is added using [[StateDeclaration.url]] or [[when]]. This api can be used directly for more control (to register a [[BaseUrlRule]], for example). Rules can be created using [[urlRuleFactory]], or created manually as simple objects.

  A rule should have a `match` function which returns truthy if the rule matched. It should also have a `handler` function which is invoked if the rule is the best match.

  #### Parameters

  - rule: any

  #### Returns () => void

  a function that deregisters the rule

  - Defined in src/router/url/url-rules.js:190

### rules

- rules(): any[]

  Gets all registered rules

  #### Returns any[]

  an array of all the registered rules

  - Defined in src/router/url/url-rules.js:203

### sort

- sort(compareFn: any): void

  Defines URL Rule priorities

  More than one rule ([[UrlRule]]) might match a given URL. This `compareFn` is used to sort the rules by priority. Higher priority rules should sort earlier.

  The [[defaultRuleSortFn]] is used by default.

  You only need to call this function once. The `compareFn` will be used to sort the rules as each is registered.

  If called without any parameter, it will re-sort the rules.

  Url rules may come from multiple sources: states's urls ([[StateDeclaration.url]]), [[when]], and [[rule]]. Each rule has a (user-provided) [[UrlRule.priority]], a [[UrlRule.type]], and a [[UrlRule.$id]] The `$id` is is the order in which the rule was registered.

  The sort function should use these data, or data found on a specific type of [[UrlRule]] (such as [[StateRule.state]]), to order the rules as desired.

  #### Example:

  This compare function prioritizes rules by the order in which the rules were registered. A rule registered earlier has higher priority.

      function compareFn(a, b) {
        return a.$id - b.$id;
      }

  #### Parameters

  - compareFn: any

    a function that compares to [[UrlRule]] objects. The `compareFn` should abide by the `Array.sort` compare function rules. Given two rules, `a` and `b`, return a negative number if `a` should be higher priority. Return a positive number if `b` should be higher priority. Return `0` if the rules are identical.

    See the mozilla reference for details.

  #### Returns void

  - Defined in src/router/url/url-rules.js:249

### stableSort

- stableSort(arr: any, compareFn: any): any

  #### Parameters

  - arr: any
  - compareFn: any

  #### Returns any

  - Defined in src/router/url/url-rules.js:273

### when

- when(matcher: any, handler: any, options: any): any

  Registers a `matcher` and `handler` for custom URLs handling.

  The `matcher` can be:

  - a [[UrlMatcher]]: See: [[UrlMatcherFactory.compile]]
  - a `string`: The string is compiled to a [[UrlMatcher]]
  - a `RegExp`: The regexp is used to match the url.

  The `handler` can be:

  - a string: The url is redirected to the value of the string.
  - a function: The url is redirected to the return value of the function.

  When the `handler` is a `string` and the `matcher` is a `UrlMatcher` (or string), the redirect string is interpolated with parameter values.

  #### Example:

  When the URL is `/foo/123` the rule will redirect to `/bar/123`.

      .when("/foo/:param1", "/bar/:param1")

  When the `handler` is a string and the `matcher` is a `RegExp`, the redirect string is interpolated with capture groups from the RegExp.

  #### Example:

  When the URL is `/foo/123` the rule will redirect to `/bar/123`.

      .when(new RegExp("^/foo/(.*)$"), "/bar/$1");

  When the handler is a function, it receives the matched value, the current URL, and the `UIRouter` object (See [[UrlRuleHandlerFn]]). The "matched value" differs based on the `matcher`. For [[UrlMatcher]]s, it will be the matched state params. For `RegExp`, it will be the match array from `regexp.exec()`.

  If the handler returns a string, the URL is redirected to the string.

  #### Example:

  When the URL is `/foo/123` the rule will redirect to `/bar/123`.

      .when(new RegExp("^/foo/(.*)$"), match => "/bar/" + match[1]);

  Note: the `handler` may also invoke arbitrary code, such as `$state.go()`

  #### Parameters

  - matcher: any

    A pattern `string` to match, compiled as a [[UrlMatcher]], or a `RegExp`.

  - handler: any

    The path to redirect to, or a function that returns the path.

  - options: any

    `{ priority: number }`

  #### Returns any

  the registered [[UrlRule]]

  - Defined in src/router/url/url-rules.js:340