RangeError: Maximum call stack size exceeded

[yverenoir]

Hi,
I am trying to parse json to xml (both in code with json2xml and with cli), but it gives me this error:

/Users/.../node_modules/xml-js/lib/js2xml.js:35
    return (!firstLine && options.spaces ? '\n' : '') + Array(depth + 1).join(options.spaces);
                                                                         ^

RangeError: Maximum call stack size exceeded
    at Array.join (native)
    at writeIndentation (/Users/.../node_modules/xml-js/lib/js2xml.js:35:74)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:37)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:83)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:83)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:83)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:83)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:83)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)
    at writeElementsCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:225:83)
    at writeElementCompact (/Users/.../node_modules/xml-js/lib/js2xml.js:204:12)

The original json file is:

{
  "vertical": {
    "-display_name": "Exercise",
    "html": { "-url_name": "12345" },
    "lti_consumer": {
      "-url_name": "12345",
      "-xblock-family": "xblock.v1",
      "-accept_grades_past_due": "false",
      "-weight": "14.0",
      "-has_score": "true",
      "-display_name": "Exercise",
      "-ask_to_send_username": "true",
      "-ask_to_send_email": "true",
      "-button_text": "Launch Exercise",
      "-custom_parameters": "none",
      "-lti_id": "id",
      "-launch_target": "new_window",
      "-launch_url": "url"
    }
  }
}

I would be grateful for any insights!

Thanks!
Yve

[yverenoir]

I tested the original xml file I had and converted it into json, it comes with "_attributes", after adjusting the json file, it solved the problem.

[nashwaan]

@yverenoir
If this is solved, should this issue be closed?

[bidiu]

@yverenoir Can you please explain more about the cause of this issue here? Cause I run into the same issue. Thanks a lot ; )

[nashwaan]

@bidiu , you probably missing "_text" property in your json input.
For example, {"a": "hi"} will not produce <a>hi</a>. The correct input is {"a":{"_text":"hi"}}.

Using, the above json input provided by @yverenoir will not work as it is missing "_text" property. The correct input should be:

{
    "vertical": {
        "-display_name": {
            "_text": "Exercise"
        },
        "html": {
            "-url_name": {
                "_text": "12345"
            }
        },
        "lti_consumer": {
            "-url_name": {
                "_text": "12345"
            },
            "-xblock-family": {
                "_text": "xblock.v1"
            },
            "-accept_grades_past_due": {
                "_text": "false"
            },
            "-weight": {
                "_text": "14.0"
            },
            "-has_score": {
                "_text": "true"
            },
            "-display_name": {
                "_text": "Exercise"
            },
            "-ask_to_send_username": {
                "_text": "true"
            },
            "-ask_to_send_email": {
                "_text": "true"
            },
            "-button_text": {
                "_text": "Launch Exercise"
            },
            "-custom_parameters": {
                "_text": "none"
            },
            "-lti_id": {
                "_text": "id"
            },
            "-launch_target": {
                "_text": "new_window"
            },
            "-launch_url": {
                "_text": "url"
            }
        }
    }
}

Which will produce this result:

<vertical>
    <-display_name>Exercise</-display_name>
    <html>
        <-url_name>12345</-url_name>
    </html>
    <lti_consumer>
        <-url_name>12345</-url_name>
        <-xblock-family>xblock.v1</-xblock-family>
        <-accept_grades_past_due>false</-accept_grades_past_due>
        <-weight>14.0</-weight>
        <-has_score>true</-has_score>
        <-display_name>Exercise</-display_name>
        <-ask_to_send_username>true</-ask_to_send_username>
        <-ask_to_send_email>true</-ask_to_send_email>
        <-button_text>Launch Exercise</-button_text>
        <-custom_parameters>none</-custom_parameters>
        <-lti_id>id</-lti_id>
        <-launch_target>new_window</-launch_target>
        <-launch_url>url</-launch_url>
    </lti_consumer>
</vertical>

For more discussion on why "_text" property is required, see the reasons here and here.

Please let me know if this solves the issue you are facing.

[nashwaan]

There is another reason why you might get this error:

If the text value should appear in the attributes of the xml node rather than its body, then "_attributes" is required. For example, {"a": {"b": "hi"}} will not produce <a b="hi">. The correct input is {"a": "_attributes": {"b": "hi"}}}

Thus, @yverenoir has probably used this input to solve his problem:

{
    "vertical": {
        "_attributes": {
            "-display_name": "Exercise"
        },
        "html": {
            "_attributes": {
                "-url_name": "12345"
            }
        },
        "lti_consumer": {
            "_attributes": {
                "-url_name": "12345",
                "-xblock-family": "xblock.v1",
                "-accept_grades_past_due": "false",
                "-weight": "14.0",
                "-has_score": "true",
                "-display_name": "Exercise",
                "-ask_to_send_username": "true",
                "-ask_to_send_email": "true",
                "-button_text": "Launch Exercise",
                "-custom_parameters": "none",
                "-lti_id": "id",
                "-launch_target": "new_window",
                "-launch_url": "url"
            }
        }
    }
}

Which will produce this xml output:

<vertical -display_name="Exercise">
    <html -url_name="12345"/>
    <lti_consumer -url_name="12345" -xblock-family="xblock.v1" -accept_grades_past_due="false" -weight="14.0" -has_score="true" -display_name="Exercise" -ask_to_send_username="true" -ask_to_send_email="true" -button_text="Launch Exercise" -custom_parameters="none" -lti_id="id" -launch_target="new_window" -launch_url="url"/>
</vertical>

[bidiu]

@nashwaan Thank you so much for replying and following up. Yes, the cause of my problem is exactly what you said. Right now I solved it.

For the record, what I was trying to do is to convert xml to js (compact version), and then process the js a little, and finally convert it back to xml. The problem is that I set some texts to the js directly. However, I should set the text to "_text" property instead. Thank you once again. The issue could be closed now I think.