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App(Object object)

Register the small program. Accept an Object parameter that specifies lifecycle callbacks for small programs, and so on.

App() must be .js in the app, must be called, and can only be called once. Otherwise, there will be u unpredictable consequences.

Parameters

Object object

Refer to the Run Mechanism section for the definition of the background before the small program and the operation mechanism of the small program.

The sample code

App({
  onLaunch (options) {
    // Do something initial when launch.
  },
  onShow (options) {
    // Do something when show.
  },
  onHide () {
    // Do something when hide.
  },
  onError (msg) {
    console.log(msg)
  },
  globalData: 'I am global data'
})

onLaunch(Object object)

Triggered when the program initialization is complete, the global trigger is triggered only once. Parameters can also be obtained using wx.getLaunchOptionsSync.

Parameter: Consistent with wx.getLaunchOptionsSync

onShow(Object object)

The small program starts, or is triggered when it enters the fore reception display from the background. You can also use wx.onAppShow to bind listening.

Parameter: Consistent with wx.onAppShow

onHide()

The small program is triggered when the front desk enters the background. You can also use wx.onAppHide binding to listen.

onError(String error)

Triggered when a script error occurs or an API call is reported. You can also use wx.onError to bind listening.

Parameter: Consistent with wx.onError

onPageNotFound(Object object)

Base Library 1.9.90 starts to support, and low versions need to be compatible.

Triggered when the page to be opened by the small program does not exist. Y ou can also use wx.onPageNotFound to bind listening. Note that please refer to wx.onPageNotFound.

Parameter: Consistent with wx.onPageNotFound

Example code:

App({
  onPageNotFound(res) {
    wx.redirectTo({
      url: 'pages/...'
    }) // 如果是 tabbar 页面，请使用 wx.switchTab
  }
})

onUnhandledRejection(Object object)

Base library 2.10.0 starts to be supported, and low versions need to be compatible.

Triggered when a small program has an unprocessed Promise deny. Y ou can also use wx.onUnhandledRejection to bind listening. For more information, please refer to wx.onUnhandledRejection.

Parameter: Consistent with wx.onUnhandledRejection

onThemeChange(Object object)

Base library 2.11.0 starts to support, and low versions need to be compatible.

Triggered when the system switches themes. You can also use wx.onThemeChange binding to listen.

Parameter: Consistent with wx.onThemeChange

AppObject getApp(Object object)

Gets a globally unique app instance to the small program.

Parameters

Object object

The sample code

// other.js
var appInstance = getApp()
console.log(appInstance.globalData) // I am global data

Attention

• Instead of calling getApp() in functions defined within app() or before calling the app, use this to get an app instance.
• Don't call lifecycle functions privately after getting an instance through getApp().