Serializable label fields

Serializable labels work exactly the same as normal labels except they also serialize to XML. They should only be used if you are editing the content of a label programmatically, and wish it to serialize to XML.

Serializable label field

Serializable label field on a collapsed block



  "type": "example_serializable_label",
  "message0": "%1",
  "args0": [
      "type": "field_label_serializable",
      "name": "FIELDNAME",
      "text": "a serializable label"


Blockly.Blocks['example_serializable_label'] = {
  init: function() {
        .appendField(new Blockly.FieldLabelSerializable("a serializable label"), "FIELDNAME");

The serializable label field takes in an optional value, and an optional css class string. Both default to an empty string.

Serialization and XML

The XML for a serializable label field looks like so:

<field name="FIELDNAME">text</field>

The field node's name attribute contains a string referencing a serializable label field, and the node's inner text is the value to apply to the field.


Serializable label fields do not support validators, because they are not editable by a user.