Question

我想在转到另一个循环之前先完成所有结果。我怎样才能实现这一目标？

function callback_Original(results, status) { 
    if (status === google.maps.places.PlacesServiceStatus.OK) { 
      for (var i = 0; i < results.length; i++) { 
                createMarker_Original(results[i]);
      }
    }
  }

有时候总会占用很少的地方。

function createMarker_Original(place) {
    var photos = place.photos;
    if (!photos) {
        return;
    }

    var placeLoc = place.geometry.location;
    var marker = new google.maps.Marker({
      map: map,
      position: place.geometry.location
    });



    google.maps.event.addListener(marker, 'click', function() { 
          infowindow.setContent('<div style="float:left"><img src="' + photos[0].getUrl({'maxWidth': 120, 'maxHeight': 120}) 
          + '"></div><div style="float:right; padding: 10px;"><b>Name: </b>'+  place.name +'<br/>'+
          '<b>Coordinates : </b>'+ place.geometry.location +'<br/>'+
          '<b>Type: </b>'+ type +'<br/>');
          infowindow.open(map, this);
    });
}

Answer 1

使用Promise怎么样？（ES6代码）

function callback_Original(results, status) {
            return new Promise((resolve, reject) => {
                if (status === google.maps.places.PlacesServiceStatus.OK) {
                    for (var i = 0; i < results.length; i++) {
                        createMarker_Original(results[i]);
                    }
                    resolve();
                }else
                    reject("Places service error");
            });
        }

然后使用

callback_Original(a,b)
.then(response => {
// Loop finished, what to do nexT?
})
.catch(error => {
// Error
console.log(error);
});

Answer 2

使用async，它会等待promise。 Reference

function callback_Original_child(results, status) { 
    return new Promise(resolve => {
        if (status === google.maps.places.PlacesServiceStatus.OK) { 
          for (var i = 0; i < results.length; i++) { 
                createMarker_Original(results[i]);
          }
        }
    });
}

async function callback_Original(results, status) { 
    try {
        await callback_Original_child(results, status);
    } catch (error) {
        console.log(error);
    }
}

callback_Original()

javascript - 等待循环先完成

2 个答案: