The use of el expression in js and the non-empty judgment method

Below I will share with you an article about the use of el expressions in js and the non-empty judgment method. It has a good reference value and I hope it will be helpful to everyone.

Note, what I want to talk about here is not the use of nested el expressions in jsp, but the use in js.

Scenario:

After the page jumps, use spring mvc to pass a json object to the front-end page. After getting it in js, Do processing.

Returned json object:

{"nodes":[{"contactmobile":"15922208502","orderno":"XNH31918062989476864"},{"id":"12198","group":"11","content":"把考虑考虑","modelname":"Company"}],"links":[{"target":"12198","id":"15016","relationType":"公司","source":"12194"}]}

var graph; 
var flag = "${empty jsonData}"; 
if(flag!="true"){ 
  graph = eval('(' + '${jsonData}' + ')'); 
};

There is a note here:

When using el expressions in js, be sure to use quotation marks. If the returned json contains double quotes, then use single quotes to surround the el expression, otherwise, use double quotes.

In addition, pay attention to the writing method of using the eval function to convert the json string into an object.

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

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