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title: Weex Variable type: references group: API order: 2.5 version: 2.1

Every Weex page contains a weex variable in its js runtime context. It can be assessed directly just like a global object, but it is readonly and separated from different pages.

NOTE: The weex variable only exposed in the Vue framework. It's not available in Rax framework yet.

Properties and Methods

The type declaration of the Weex variable is:

declare type Weex = {
  config: WeexConfigAPI;
  document: WeexDocument;
  requireModule: (name: string) => Object | void;
  supports: (condition: string) => boolean | void;
}

config

The weex.config contains all the environment information of current page.

declare type WeexConfigAPI = {
  bundleUrl: string;
  bundleType?: string;
  env: WeexEnvironment;
}

• bundleUrl: The URL of the js bundle in current page.
• bundleType: v0.17+ The type of the js bundle, it indicates which framework is using for current js bundle, could be "Vue" or "Rax".
• env: Weex environment object.

Weex Environment Object

Sometimes, you still need to write some platform specific codes for compatibility or enhancement. Weex provides weex.config.env and a global object WXEnvironment (they are strictly equal) to get the information of current runtime environment.

weex.config.env === WXEnvironment

Properties in Weex environment object:

Property	Type	Description
platform	String	Current running platform, could be “Android”, “iOS” or “Web”.
weexVersion	String	The version of Weex SDK.
appName	String	Mobile app name or browser name.
appVersion	String	The version of current app.
osName	String	The OS name, could be “Android” or “iOS”.
osVersion	String	The version of current OS.
deviceModel	String	Mobile phone device model. (native only)
deviceWidth	Number	Screen resolution width.
deviceHeight	Number	Screen resolution height.

This example prints all properties in the Weex environment object.

document

The weex.document is the document object of current page, it can be used to create or manipulate the Elements in DOM tree. It's part of Weex DOM API specification which is NOT the same with the document object in the W3C DOM API.

However, it's not a good practice to manipulate DOM directly when using modern front-end frameworks, such as Vue and Rax. Especially, there is no actually DOM in Weex, it was simulated on the native (Android or iOS).

This API is mainly used inside of the Vue and Rax framework to convert the virtual-dom into render directives and send them to native render engines of Weex. Not recommended for using it when developing pages.

requireModule

For those features which does not rely on the UI, Weex wraps them into modules. It is a way to access native capabilities in javascript. Except for the built-in modules, it's quite easy to integrate the existing native modules to Weex platform. After that, you can use weex.requireModule to require both customized and built-in modules.

weex.requireModule(name: string): Object | void;

Parameter:

• A case-sensitive module name.

Return Value:

• If the module is registered, return a Proxy or plain object if the context doesn't support Proxy. You can use it to call the registered methods in the module.
• If the module is unregistered, return undefined.

Use Native Module

You can require a native module and use its APIs just like normal javascript functions. Here is a simple example of using the modal module:

<template>
  <div><text>Toast</text></div>
</template>
<script>
  const modal = weex.requireModule('modal')
  modal.toast({
    message: 'I am a toast.',
    duration: 3
  })
</script>

supports

This API only available in v0.15+.

As you may know, components and modules are extendable and configurable in Weex. So it could be various in different apps or running context. You can use weex.supports to detect whether a feature is supported in the current environment at runtime.

weex.supports(condition: string): boolean | void;

Parameter:

• A formatted condition string: @{type}/{name}.

The type must be "component" or "module". The name could be a tag name, module name or the method name in specific module.

Return Value:

• If the feature is supported, return true.
• If the feature is unsupported, return false.
• If not sure about whether this feature is supported, return null.

Examples

Detects whether the specific component is supported:

weex.supports('@component/slider') // true
weex.supports('@component/my-tab') // false

Detects whether the specific module is supported:

weex.supports('@module/stream')  // true
weex.supports('@module/abcdef')  // false

Detects whether the method in specific module is supported:

weex.supports('@module/dom.getComponentRect') // true
weex.supports('@module/navigator.jumpToPage') // false

Invalid input or unknown features:

weex.supports('div') // null
weex.supports('module/*') // null
weex.supports('@stream/fetch') // null
weex.supports('getComponentRect') // null

isRegisteredModule

Detect whether the specific module or method is registered.

weex.weex.isRegisteredModule(moduleName: string, methodName: string): boolean

It can only be used to check compatibility of a specific module or method.

weex.isRegisteredModule('stream') // true
weex.isRegisteredModule('stream', 'fetch') // true
weex.isRegisteredModule('whatever', '- unknown -') // false
weex.isRegisteredModule('div') // false, not support components

isRegisteredComponent

Detect whether the specific component is registered.

weex.weex.isRegisteredComponent(componentName: string): boolean

It can only be used to check compatibility of a specific component.

weex.isRegisteredComponent('div') // true
weex.isRegisteredComponent('- unknown -') // false
weex.isRegisteredComponent('navigator') // false, not support modules