Relay: Support readInlineData with @relay(plural: true) Fragments

[derekdowling]

Despite spread the fragment in the parent that is passing the ref to the function, you get a runtime error when attempting to use readInlineData on a Fragment that uses the plural: true directive such as:

function filter(itemsRef) {
  const items = readInlineData(
    graphql`
      fragment ItemList_items on Item @relay(plural: true) {
        name
      }
    `,
     itemsRef
  );

  // process
}

Error:

readInlineData(): Expected fragment `ItemList_items` to be spread in the parent fragment.

I also tried mapping with readInlineData, but that didn't work either:

function filter(itemsRef) {
  const items = itemsRef.map(i => readInlineData(
    graphql`
      fragment ItemList_items on Item @relay(plural: true) {
        name
      }
    `,
     i
  );

  // process
}

Presumably readInlineData is expecting an object that contains a specific fragment ref key rather than an array of fragments.

[taion]

We're hitting this too, but I wonder if the answer here isn't just "don't use @relay(plural)"? The plural annotation seems like it'd mostly just be a signal to the fragment container to expect an array.

But in this case, couldn't you just make the fragment non-plural, then iterate over each instance?

[Daniel15]

I hit the same issue. It should work if you iterate over the array (as per your second code snippet) if you remove @relay(plural: true) from the fragment.

const items = itemsRef.map(i => readInlineData(
  graphql`
    fragment ItemList_items on Item {
      name
    }
  `,
   i
);

The other way I've worked around this issue is by passing in a connection rather than a raw array, for example:

const items = readInlineData(
  graphql`
    fragment ItemList_items on ItemConnection {
      nodes {
        name
      }
    }
  `,
  itemsRef,
);
// use items.nodes

[stale[bot]]

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