将参数从不同的函数发送到一个函数

Question

    function layerQuery(objectId) {
    const featureLayer = view.map.layers.getItemAt(0);
    const queryParams = featureLayer.createQuery();
   

    queryParams.where = "objectid=" + objectId;
    queryParams.outFields = ["x", "y", "z"];

    featureLayer.queryFeatures(queryParams).then(function (results) {
      const coords = results.features[0].attributes;
      direction_lookup(Promise, Promise,coords.x,coords.y)
    });
    const objectIdNext = objectId + 1
    const queryParamsTb = featureLayer.createQuery();
    queryParamsTb.where = "objectid=" + objectIdNext;
    queryParamsTb.outFields = ["x", "y", "z"];
    featureLayer.queryFeatures(queryParamsTb).then(function (results) {
      var coordstb = results.features[0].attributes;
      direction_lookup(coordstb.x, coordstb.y,Promise,Promise)
    });
    //console.log(coordstb.x)
    
  }

我想把上面两个函数得到的四个参数传给下面的函数

function direction_lookup(destination_x, origin_x, destination_y, origin_y) {
    var compass_brackets, compass_lookup, degrees_final, degrees_temp, deltaX, deltaY;
    deltaX = destination_x - origin_x;
    deltaY = destination_y - origin_y;
    degrees_temp = Math.atan2(deltaX, deltaY) / Math.PI * 180;
    

    if (degrees_temp < 0) {
      degrees_final = 360 + degrees_temp;
    } else {
      degrees_final = degrees_temp;
    }

    compass_brackets = ["N", "NE", "E", "SE", "S", "SW", "W", "NW", "N"];
    compass_lookup = Math.round(degrees_final / 45);
    return [compass_brackets[compass_lookup], degrees_final];
  }

  console.log(direction_lookup(destination_x, origin_x, destination_y, origin_y));

'direction lookup'函数有四个参数。我想从不同的函数中两个两个地发送这四个参数。我可以这样做吗

Answer 1

您尝试执行的操作是不可能的，因为您的 direction_lookup 函数需要这四个参数作为数字 co-ordinates，它不希望看到任何 Promise 对象或解决它们。执行此操作的标准方法是等到知道所有值后再调用函数，如下所示：

function layerQuery(objectId) {
    const featureLayer = view.map.layers.getItemAt(0);
    const queryParams = featureLayer.createQuery();
   

    queryParams.where = "objectid=" + objectId;
    queryParams.outFields = ["x", "y", "z"];

    featureLayer.queryFeatures(queryParams).then((results) => {
      const feature1Coords = results.features[0].attributes;
      const objectIdNext = objectId + 1
      const queryParamsTb = featureLayer.createQuery();
      queryParamsTb.where = "objectid=" + objectIdNext;
      queryParamsTb.outFields = ["x", "y", "z"];
      featureLayer.queryFeatures(queryParamsTb).then((secondResults) => {
         const feature2Coords = secondResults.features[0].attributes;
         direction_lookup(feature2Coords.x, features2Coords.y,feature1Coords.x,feature1Coords.y);
      });
    }); 
   }

现在执行第一个查询并在执行第二个查询时将结果保留在范围内，最后在两组 co-ordinates 准备就绪时调用 direction_lookup。

Arrow functions 表现得像常规函数，但保留了父作用域，这可以避免很多混乱，所以对于这种任务，它是一种稍微方便一些的表示法。

将参数从不同的函数发送到一个函数

Sending parameters from different functions to a function

javascript

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