(Tcl) Call a JavaScript Function Returning a Boolean

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Note: This example requires Chilkat v11.4.0 or greater.

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load ./chilkat.dll

set success 0

# This is the JavaScript function we'll call:

# function isEven(number) {
#     return number % 2 === 0;
# }

set sbScript [new_CkStringBuilder]

CkStringBuilder_Append $sbScript "function isEven(number) { return number % 2 === 0; }"

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 isEven(8)

set funcCall [new_CkJsonObject]

# Create JSON specifying the function name and arguments

# {
#   "name": "isEven",
#   "args": [ 8 ]
# }

CkJsonObject_UpdateString $funcCall "name" "isEven"
CkJsonObject_UpdateInt $funcCall "args[0]" 8

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": "bool",
#   "value": true
# }

set retval [CkJsonObject_BoolOf $result "value"]
puts "$retval"

# Output:
# 1

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