3

I have a object with printout from a console.log() command:

console.log("event in validation ", this.event_info);

Here is the printout:

event in validation  {"start_datetime":"Sun Jul 14 2019 18:20:00 GMT-0700 (PDT)","finish_datetime":"Mon Jul 15 2019 18:20:00 GMT-0700 (PDT)"}

There are 2 fields in this.event_info: start_datetime and finish_datetime. I need to refer the value of finish_datetime and did the following:

this.event_info["finish_datetime"];

and

let sd = "finish_datetime";
this.event_info[sd];

But there are nothing retrieved (undefined or nothing). Then I tried to print out the keys of the object:

 Object.keys(this.event_info);

And printout is:

 [ '0',
  '1',
  '2',
  '3',
  .
  .
  .
  99

Then I tried these:

 this.event_info["1"];

and:

this.event_info[1];

It is nothing printed out again. What is the right way here to refer the value of finish_datetime?

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7
  • Are you sure you don't overwrite the variable? You should show us the entire code to see where the problem comes from Commented Jul 15, 2019 at 6:24
  • 6
    this.event_info is a JSON string. You want JSON.parse(this.event_info).finish_datetime Commented Jul 15, 2019 at 6:25
  • @Phil I bet your comment is right, don't you want to write an answer with that info? If this is not a duplicate it is a good question. Commented Jul 15, 2019 at 6:28
  • 1
    @RaulSauco I'd say it classifies as a typo / no longer a problem. A modicum of debugging (like with a debugger) would reveal the data type of OP's variable. The only real take-away from this is that console.log() is not a debugging tool. Commented Jul 15, 2019 at 6:31
  • 1
    Object.keys(obj) returns the keys of your object. Object.values(obj) returns the values and Object.entries(obj) returns an array of arrays ([key, value]) - developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…. So it's not surprising that for Object.keys(obj) you get an array of numbers. Commented Jul 15, 2019 at 6:32

1 Answer 1

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Long Answer

console.log() is a terrible debugging tool. It does not show data types and what it shows is not always a correct representation of the state of your application at the time you call it.

You should instead use your browser's actual debugger or one connected via your editor / IDE.

Short Answer

Your variable is a JSON string, not an object. You want

JSON.parse(this.event_info).finish_datetime
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1 Comment

Save my day and thank you! I was confused by w3schools.com/js/js_json_objects.asp and treated it as JSON object instead of JSON string.

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