Finally in promise

Promise In addition to the commonly used then and catch Outside ,finally It's also very important .

One 、finally The role of

         No matter promise The final state , The execution of the then or catch After the specified callback function , It will be carried out finally Callback function specified by method .

Two 、 Application scenarios

        In projects, we often encounter some functions of loading effects , Generally, the page displays the loading effect before the request , Cancel the page loading effect after the request is completed , I first put the logo on then Go inside and deal with , Later, I found that if the request is wrong , The page has been loaded and cannot be cancelled , Put the logo on the finally To deal with , So it solved the problem

 equipmentApi
            .adddingNode(data)
            .then(({ code, message }) => {
              if (code === 200) {
                this.$message.success(" Added successfully ！");
                this.getTreeData();
                this.handleCheck();
                this.cancel();
              } else if (code === 40001) {
              } else {
                this.$message.error(message);
              }
            })
            .finally(() => {
              this.buttonLoading = false;
            });