CODEWITHSUNDEEP
javascriptreactjsreact-native
Jack23
Jack23

Reputation: 1396

Order of execution in ComponentDidMount

I have a question:

I have 4 functions that I wrote in the componentDidMount(), but I notice that the order in which I write these functions is not respected. 

componentDidMount() {
    this.checkPermission(); (1)
    this.checkInitialBluetoothState(); (2)
    this.disconnect() (3)
    this.scans() (4)
  }

I receive the console log in order from; (3) (2) (1) and (4) and sometimes the (4) function is not performed and the app enters in a loop

Do you recommend linking one function to another by calling it?

Thank you

EDIT:

async checkPermission() {
    try {
      const granted = await PermissionsAndroid.request(
        PermissionsAndroid.PERMISSIONS.ACCESS_COARSE_LOCATION,
        {
          title: 'Accesso Localizzazione',
          message: 'Richiesto accesso localizzazione',
          buttonNegative: 'Cancel',
          buttonPositive: 'Ok',
        },
      );
      if (granted === PermissionsAndroid.RESULTS.GRANTED) {
        console.log("Accesso Localizzazione Permesso.")
      }
      else {
        console.log("Accesso Localizzazione Negato.")
      }
    } catch (err) {
      console.warn(err)
    }
  }


  async checkInitialBluetoothState() {
    const isEnabled = await BluetoothStatus.state();
    console.log("Controllo bluetooth on o off", isEnabled);
    if (isEnabled == true) {
      console.log("Bluetooth attivo.")
    }
    else {
      Alert.alert(
        'Attenzione:',
        'Bluetooth non è attivo.'
      );
      Actions.homepageutente();
    }
  }


  disconnectDevice() {
    if (this.state.device1) {
      this.manager.cancelDeviceConnection(this.state.device1.id)
    }
    else {
      console.log("Device1 non connesso")
    }
    if (this.state.device2) {
      this.manager.cancelDeviceConnection(this.state.device2)
    }
    else {
      console.log("Device2 non connesso")
    }
  }


  scans() {
//....

Upvotes: 0

Views: 165

Answers (1)

Davin Tryon
Davin Tryon

Reputation: 67296

If you need async functions to execute in order. Do something like this:

async componentDidMount() {
    await this.checkPermission(); (1)
    await this.checkInitialBluetoothState(); (2)
    this.disconnect() (3)
    this.scans() (4)
  }

Otherwise, the async functions will return immediately.

Upvotes: 4

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