New required field default

[momoneko]

Hi,

I'm trying to add a new required field to our content types.

How would I go about setting the default value for it in the existing entries?

[ethan-ozelius-contentful]

Hello Momoneko, thanks for raising this issue.

I tested this out a bit in the web app, and at least for a Number type field, previously existing entries did not automatically get updated with the default value I set at the content type level. Which makes me think this could be an API limitation, intentional or otherwise.

As a work-around, I might suggest

1. updating the content type with the default value
2. querying for all entries of that type, and updating that field with the default value

maybe something like:

// add-age-to-author.js

module.exports = (migration) => {
  // Get the existing author content type
  const author = migration.editContentType('author');

  // Add the new age field
  author.createField('age')
    .name('Age')
    .type('Integer')
    .localized(false)
    .required(false)
    .validations([
      {
        range: {
          min: 1,
          max: 150
        }
      }
    ])
    .defaultValue({
      'en-US': 1
      // add any other locales
    });

  // Optional: Add help text for editors
  author.changeFieldControl('age', 'builtin', 'numberEditor', {
    helpText: 'Enter the author\'s age (must be between 1 and 150)'
  });
};

Once that migration is complete, update the entries of type author to add a default value if not already set. Note: you'll want to decide ahead of time if you'd like to actually publish those changes, or leave them in a draft state

module.exports = (migration, { makeRequest }) => {
  // Transform all entries of the author content type
  migration.transformEntries({
    contentType: 'author',
    from: ['age'], // We only need to read the age field
    shouldPublish: true, // Publish the changes after transformation
    transformEntryForLocale: async (fromFields, currentLocale, { id }) => {
      console.log(`Processing Author entry: ${id}`);
      
      // Check if age field exists and has a value
      const currentAge = fromFields.age;
      
      if (currentAge === undefined || currentAge === null) {
        console.log(`  Setting age to 1 for entry ${id} (was ${currentAge})`);
        return {
          age: 1
        };
      }
      
      console.log(`  Skipping entry ${id} - age already set to: ${currentAge}`);
      return fromFields;
    }
  });
};

I might suggest checking out these helpful examples/docs:

Making changes to existing entries

Making changes to a field of a content type

Hopefully that helps.

[ethan-ozelius-contentful]

Not sure if these two issues are related, but cross-posting for posterity

#1523