Javascript object attribute is accessible but gives undefined error

Question

I am trying to work with data sent from a server using the following code where msg is the incoming data that holds two arrays:

console.log(msg);
for (var i = 0; i <= msg.cues.length; i++) {
  $("#cues").append("<div class=\"cue-item\" cueval=\"cue-" + i + "\"><h4>"+msg.cues[i].name+"</h4>"+msg.cues[i].description+"</div>");
}

This code adds the required elements to the page and everything seems to be fine from the browser window, but in the console I get the below error that blocks all other code from running:

{…}
  channels: Array [ 0, 0, 0, … ]
  cues: […]
    0: Object { name: "Cue 1", description: "This is a test cue" }

TypeError: msg.cues[i] is undefined

Any idea why this is happening and how I can solve this issue?

The for statement is wrong, it should be for (var i = 0; i < msg.cues.length; i++) — Marcelo Origoni
– Marcelo Origoni, Commented Dec 18, 2017 at 2:40

Robby Cornelissen · Accepted Answer · 2017-12-18 02:40:40Z

3

You're iterating one position past the length of the array. Change

for (var i = 0; i <= msg.cues.length; i++)

to

for (var i = 0; i < msg.cues.length; i++)

answered Dec 18, 2017 at 2:40

Robby Cornelissen

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Comments

Vasyl Moskalov · Accepted Answer · 2017-12-18 02:41:12Z

1

Replace <= to < in for-loop head

answered Dec 18, 2017 at 2:41

Vasyl Moskalov

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