Tcl Requires Chilkat v11.4.0+

Call a JavaScript Function Returning an Object

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Demonstrates how to call a JavaScript function that returns an object. Tcl

load ./chilkat.dll

set success 0

#  This is the JavaScript function we'll call:

#  function getSettings() {
#      return {
#          theme: "dark",
#          notifications: true,
#          version: 1.0
#      };
#  }

set sbScript [new_CkStringBuilder]

CkStringBuilder_Append $sbScript "function getSettings() {"
CkStringBuilder_Append $sbScript "    return {"
CkStringBuilder_Append $sbScript "        theme: \"dark\","
CkStringBuilder_Append $sbScript "        notifications: true,"
CkStringBuilder_Append $sbScript "        version: 1.0"
CkStringBuilder_Append $sbScript "    };"
CkStringBuilder_Append $sbScript "}"

set js [new_CkJs]

set result [new_CkJsonObject]

CkJsonObject_put_EmitCompact $result 0

#  Call Eval to add the function to the context's global object
set success [CkJs_Eval $js $sbScript $result]
if {$success == 0} then {
    #  Examine the result for an exception.
    puts [CkJsonObject_emit $result]

    #  Also examine the LastErrorText.
    puts [CkJs_lastErrorText $js]
    delete_CkStringBuilder $sbScript
    delete_CkJs $js
    delete_CkJsonObject $result
    exit
}

#  ------------------------------------------------------------------------------
#  Call the function getSettings()

set funcCall [new_CkJsonObject]

#  Create JSON specifying the function name and arguments
#  The function has no arguments, so we only specify the name.

#  {
#    "name": "getSettings",
#  }

CkJsonObject_UpdateString $funcCall "name" "getSettings"

set success [CkJs_CallFunction $js $funcCall $result]
if {$success == 0} then {
    #  Examine the result for an exception.
    puts [CkJsonObject_emit $result]

    #  Also examine the LastErrorText.
    puts [CkJs_lastErrorText $js]
    delete_CkStringBuilder $sbScript
    delete_CkJs $js
    delete_CkJsonObject $result
    delete_CkJsonObject $funcCall
    exit
}

puts [CkJsonObject_emit $result]

#  Output:
#  {
#    "type": "object",
#    "value": {
#      "theme": "dark",
#      "notifications": true,
#      "version": 1
#    }
#  }

#  Examine the object's members
puts "theme: [CkJsonObject_stringOf $result value.theme]"
puts "notifications: [CkJsonObject_BoolOf $result value.notifications]"
puts "version: [CkJsonObject_IntOf $result value.version]"

#  Output:
#  theme: dark
#  notifications: True
#  version: 1

delete_CkStringBuilder $sbScript
delete_CkJs $js
delete_CkJsonObject $result
delete_CkJsonObject $funcCall