使用 if 语句删除 Leaflet 弹出窗口中的 "null" 属性

Question

我正在使用外部 geojson 属性来填充 Leaflet 中的弹出窗口 windows，如下所示：

function popUp (feature, geojson) {
var popupText=
"/*Name:*/" + feature.properties.name  + 
"/*Amount*/" + feature.properties.amounts;
geojson.bindPopup(popupText);
};

问题：有些金额是 "null"。那么，我该如何编写 if 语句，以便如果金额为 "null"，则字符串 ("Amount") 和属性 ("null") 都不会出现在弹出窗口中？

Answer 1

您要查找的是条件语句：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else

var popupText = '';

if (feature.properties.name) {
    popupText += '/*Name:*/' + feature.properties.name;
}

if (feature.properties.amount) {
    popupText += '/*Amount*/' + feature.properties.amount;
}

geojson.bindPopup(popupText);

或者使用条件三元运算符甚至更短：

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Conditional_Operator

var popupText = '';

popupText += (feature.properties.name) ? '/*Name:*/' + feature.properties.name : '';

popupText += (feature.properties.amount) ? '/*Amount*/' + feature.properties.amount : '';

geojson.bindPopup(popupText);