如何访问包含点的变量？

Question

Following is my script

var err=activityLocal.message;
var text="";
var i;
    for (i = 0; i < err.length; i++) {
            text+= err[i].message +";";
}
document.write(text);

Here the value of activityLocal.message as shown below:

[{
  "message": "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'manaed_server_4'.",
  "severity": "FAILURE"
}, {
  "message": "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'managed_server_3'.",
  "severity": "FAILURE"
}];

But the output is undefined , seems like JS engine gets confused with the dot in activityLocal.message variable. How can I resolve this error?

Answer 1

In your code their is problem with variable name it should not contain dot it is illegal .

var activityLocal_message = [{
  "message": "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'manaed_server_4'.",
  "severity": "FAILURE"
}, {
  "message": "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'managed_server_3'.",
  "severity": "FAILURE"
}];

var err=activityLocal_message;
var text="";
var i;
    for (i = 0; i < err.length; i++) {
            text+= err[i].message +";";
            //console.log(err[i].message);
}
console.log(text);

or else if you really want to use with dot operator try this

You can't use variables in dot notation (short of using eval, which you don't want to do). With dot notation the property name is essentially a constant.

myObj.propName
// is equivalent to
myObj["propName"]

Answer 2

You can use array map function to loop through all messages in the activityLocal.message which will return array of strings and the join them using array join function like this:

 var err= [{ "message": "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'manaed_server_4'.", "severity": "FAILURE" }, { "message": "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'managed_server_3'.", "severity": "FAILURE" }]; var text= err.map(function(e) { return e.message; }).join(";"); alert(text);

Answer 3

The array is able loop the values but the problem might be setting it in the html. below is the code and you can also check in the Plunker

// Code goes here

var activityLocal = {};
activityLocal.message = [
  {
    message:
      "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'manaed_server_4'.",
    severity: 'FAILURE',
  },
  {
    message:
      "Data Source 'TestDataSource' is in a state incompatible with this operation at server 'managed_server_3'.",
    severity: 'FAILURE',
  },
];
var err = activityLocal.message;
var text = '';
var i;
for (i = 0; i < err.length; i++) {
  text += err[i].message + ';';
  //alert(text);
}
document.getElementById('showtext').innerHTML = 'tttt' + text;

Answer 4

If you mean that you want to use the dot as the variable name, it is simply not possible.

If you want to use it as an object variable, it is accessible via the object.variableName . E. g. assume your object is named myObj and you variable assigned to that object is called myVar you can access it with this call: myObj.myVar . Or you can also iterate over the object using the for (or foreach in modern JavaScript runtime environments) loop.