Default Value When Adding New Field

Question

I am programatically adding new fields to a list through Javascript. My code looks like:

var addColumnToList = function(title, fieldName, type) {
    var context = SP.ClientContext.get_current();
    var list = context.get_web().get_lists().getByTitle(title);
    this.field = list.get_fields().addFieldAsXml("<Field DisplayName='" + fieldName + "' Type='" + type + "' />", true, SP.AddFieldOptions.defaultValue);

    var fieldNumber = context.castTo(field, SP.FieldNumber);
    fieldNumber.update();

    context.load(field);
    context.executeQueryAsync(
        Function.createDelegate(this, this.onColAddSuccess),
        Function.createDelegate(this, this.onColAddFail)
    );
};

var onColAddSuccess = function() {
    console.log(field.get_title() + " successfully added to list!\n");
};

var onColAddFail = function(sender, args) {
    console.log("Add column request failed! " + args.get_message());
};

The default value of every item defaults to "null". My question is: Is there any way to specify a default value for all items when adding a new field to a SP list?

Answer 1

Yes, you must use Default element (child of Field element) in Field XML.

UPDATE:

Example based on your code:

var addColumnToList = function(title, fieldName, type, defaultValue) {
    var context = SP.ClientContext.get_current();
    var list = context.get_web().get_lists().getByTitle(title);
    this.field = list.get_fields().addFieldAsXml(
        "<Field DisplayName='" + fieldName + "' Type='" + type + "'>" +
            "<Default>" + defaultValue + "</Default>" +
        "</Field>",
        true,
        SP.AddFieldOptions.defaultValue
    );

    context.load(field);
    context.executeQueryAsync(
        Function.createDelegate(this, this.onColAddSuccess),
        Function.createDelegate(this, this.onColAddFail)
    );
};