Tcl

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