Question

所以我想转动我的＃34; loading＆＃34;用ng-show打开和关闭gif。在脚本通过forEach加载数组完成后，我特别想关闭它。

如何在forEach完成整个周期＆＃34;时运行代码。类似于.then()的内容，但适用于for循环

function selectAll(bool) {
  vm.selectAllSpinner = true;
  vm.practicesLeftCol = [];
  if(bool === true){
    vm.practices.forEach(function(practice){
      practice.selected = true;
      vm.practicesLeftCol.push(practice)
    })
    I want this after the foreach ->vm.selectAllSpinner = false;

  } else if (bool === false){
    vm.practices.forEach(function(practice){
      practice.selected = false;
      vm.practicesLeftCol = [];
    })
    I want this after the foreach ->vm.selectAllSpinner = false;

  }

Answer 1

所以forEach不是异步的。因此，你可以写下来：

function selectAll(bool) {
          vm.selectAllSpinner = true;
          vm.practicesLeftCol = [];
          if(bool === true){
            vm.practices.forEach(function(practice){
              practice.selected = true;
              vm.practicesLeftCol.push(practice)
            })
          } else if (bool === false){
            vm.practices.forEach(function(practice){
              practice.selected = false;
              vm.practicesLeftCol = [];
            })
          }
    vm.selectAllSpinner = false;
}

话虽如此，我认为代码一般可以清理得更像：

  function selectAll(bool) {
    vm.selectAllSpinner = true;
    vm.practicesLeftCol = [];
    if (bool) {
      vm.practicesLeftCol = vm.practices.reduce(function(memo, practice) {
        practice.selected = true;
        memo.push(practice);
        return memo;
      }, []);
    }
   vm.selectAllSpinner = false; 
}

同样，reduce和forEach都不是异步的，所以这应该有点工作......

Answer 2

在Javascript中，使用分号（;）分隔符（可选地后跟换行符）将命令附加到上一个命令。因此

function selectAll(bool) {
    vm.selectAllSpinner = true;
    vm.practicesLeftCol = [];
    if(bool === true){
        vm.practices.forEach(function(practice){
            practice.selected = true;
            vm.practicesLeftCol.push(practice)
        });
        vm.selectAllSpinner = false;  //<---
    } else if (bool === false) {
        vm.practices.forEach(function(practice){
            practice.selected = false;
            vm.practicesLeftCol = [];
        });
        vm.selectAllSpinner = false; //<---
    }
}

Answer 3

不幸的是，每个没有回调 - 但你可以这样做：

  if(bool === true){
        vm.practices.forEach(function(practice){
          practice.selected = true;
          vm.practicesLeftCol.push(practice);
           items++;
           if(items === your_array.length) {
             vm.selectAllSpinner = false;
           }
        })

      }

Javascript如何在forEach完成执行后运行一些代码

3 个答案: