突破承諾鏈

Question

如何突破Promise鏈（處理錯誤並停止運行其他.then）？

我的代碼：

onSubmit(f: any) {
    let loading = this.loadingCtrl.create({
        content: 'Sending a form...'
    });
    loading.present();
    this.submitProvider.sendByPost(f)
    .then(
        (res) => { this.formSent = true, console.log('Form is sent') },
        (err) => { console.log('Encountered an error...') 
            //error here, break out and deal with error            
        } 
    )
    .then( (res) => {
        loading.dismiss();
        this.pushPage(); 
        this.removeChosenPicture();
        this.removeTakenPicture();
        this.myForm.reset({ selectedDate: this.selectedDate }) }
    )
}

Answer 1

您可以使用catch()方法：通過這樣做，您將處理promise鏈中的所有錯誤。 當錯誤在鏈中的任何地方拋出時，它將“脫離” promise鏈並最終以catch方法結束。 MDN：.catch（）方法

onSubmit(f: any) {
    let loading = this.loadingCtrl.create({
        content: 'Sending a form...'
    });
    loading.present();
    this.submitProvider.sendByPost(f)
    .then(
        (res) => { this.formSent = true, console.log('Form is sent') }
    )
    .then( (res) => {
        loading.dismiss();
        this.pushPage(); 
        this.removeChosenPicture();
        this.removeTakenPicture();
        this.myForm.reset({ selectedDate: this.selectedDate }) }
    ).catch((err) =>{ /*Handle your errors*/})
}