test.js

// dynamic character array
var charCodes = [];

// shortcut dictionary
var dict = {
    "TY": "Thanks for your request.",
    "AQ": "Let me know if you have additional questions.",
    "MY": "I look forward to meeting you.",
    "GD": "Have a great day.",
    "LONG": "This is another longer text.",
};

document.getElementById("txTemplateDesignerContainer").addEventListener("keypress", (event) => {

    // if SPACE is pressed
    if (event.charCode === 32) {

        // convert array to string to get typed word
        var typedWord = String.fromCharCode(...charCodes);

        // check word in dictionary
        if (dict[typedWord] != undefined) {

            // cancel SPACE for TXTextControl
            event.cancelBubble = true;

            // select shortcut and replace with long text
            TXTextControl.inputPosition.getTextPosition(function (startPos) {
                TXTextControl.select(startPos - typedWord.length, typedWord.length, function () {
                    TXTextControl.selection.setText(dict[typedWord] + " ");
                })
            })

        }

        // reset character array
        charCodes = [];
    } else {
        // add character to array
        charCodes.push(event.charCode);
    }

}, true);