public isValid()

in legacy/src/Calendar/Dialogs.ts [823:853]
28 lines of code
8 McCabe index (conditional complexity)

    public isValid(): boolean {
        let fieldText = $.trim(this.getValue()),
            relativeToFieldText = $.trim(this._options.relativeToField.val()),
            fieldDate,
            relativeToFieldDate,
            result = false;

        if (fieldText && relativeToFieldText) {
            fieldDate = Utils_Date.parseDateString(fieldText, this._options.parseFormat, true);
            relativeToFieldDate = Utils_Date.parseDateString(relativeToFieldText, this._options.parseFormat, true);
        } else {
            return true;
        }

        if (
            fieldDate instanceof Date &&
            !isNaN(fieldDate.getTime()) &&
            relativeToFieldDate instanceof Date &&
            !isNaN(relativeToFieldDate.getTime())
        ) {
            if (this._options.comparison === DateComparisonOptions.GREATER_OR_EQUAL) {
                result = fieldDate >= relativeToFieldDate;
            } else {
                result = fieldDate <= relativeToFieldDate;
            }
        } else {
            result = true;
        }

        return result;
    }