javascript - 检查jquery映射对象是否为null？ 适用于IE和Chrome浏览器(Check jquery map object null or not ? for both IE and Chrome browser)

Question

如何在chrome和IE浏览器中检查javascript映射对象是否为null或为空？

  ask by Vicky Singh Gill translate from so

Answer 1

Add this to code for IE browser support in your javascript :

(将此添加到您的javascript中的IE浏览器支持代码中：)

if (!Object.entries)
  Object.entries = function( obj ){
    var ownProps = Object.keys( obj ),
        i = ownProps.length,
        resArray = new Array(i); // preallocate the Array
    while (i--)
      resArray[i] = [ownProps[i], obj[ownProps[i]]];

    return resArray;
  };

For Chrome not required due to polyfill default avaialble.

(对于Chrome，由于polyfill默认可用，因此不需要。)

To check the map is null or not :

(要检查地图是否为空：)

if(Object.entries(mapObj).length > 0){}