You can just set the autoSize property of the TextField
For Example:
myTextField.autoSize = "left"
If autoSize is set to TextFieldAutoSize.LEFT, the text is treated as left-justified text, meaning that the left margin of the text field remains fixed and any resizing of a single line of the text field is on the right margin. If the text includes a line break (for example, "\n" or "\r"), the bottom is also resized to fit the next line of text.