TypeScript pulumi.all() and output#apply()

example.ts

import * as pulumi from '@pulumi/pulumi';
import { PulumiFn } from '@pulumi/pulumi/automation';

type Node = {
  role: pulumi.Output<string>;
};

// 'simple' way of faking an output is to wrap it in a promise, which should test our ability to
// wait on its value via pulumi.all, pulumi.output:
function mkOutputString(value: string): pulumi.Output<string> {
  return pulumi.output(Promise.resolve(value));
}

// Create output "nodes" that are a lot like real resources, they are output objects, but you can
// also access the keys of the object & those are outputs as well.
function mkNode(role: string): pulumi.Output<pulumi.UnwrappedObject<Node>> {
  return pulumi.output(
    Promise.resolve({
      role: mkOutputString(role),
    }),
  );
}

const nodes = [
  mkNode("foo"), // an output containing keys that are also outputs
  mkNode("bar"), // likewise
];

const k0sConfig = pulumi.all(nodes).apply((nodes) => ({
  spec: nodes.map((n) => ({
    // 💥💥💥💥💥
    // kind: mkOutputString("bar"),
    // 💥💥💥💥💥
    // ^ if I uncomment this, I get the same error you did
    role: n.role,
  })),
}));

// With line 32 commented out, this works:
k0sConfig.apply((cfg) => pulumi.log.info(JSON.stringify(cfg)));

// But with line 32 uncommented, I get an error pretty printed as follows:
const error = {
  "spec": [
    {
      "kind": "Calling [toJSON] on an [Output<T>] is not supported.\n\nTo get the value of an Output as a JSON value or JSON string consider either:\n    1: o.apply(v => v.toJSON())\n    2: o.apply(v => JSON.stringify(v))\n\nSee https://pulumi.io/help/outputs for more details.\nThis function may throw in a future version of @pulumi/pulumi.",
      "role": "foo"
    },
    {
      "kind": "Calling [toJSON] on an [Output<T>] is not supported.\n\nTo get the value of an Output as a JSON value or JSON string consider either:\n    1: o.apply(v => v.toJSON())\n    2: o.apply(v => JSON.stringify(v))\n\nSee https://pulumi.io/help/outputs for more details.\nThis function may throw in a future version of @pulumi/pulumi.",
      "role": "foo"
    }
  ]
};


// Fix is to pulumi.output() everything all at once:
const k0sctrl = mkNode('kubernetes-kind');

const k0sConfig2 = pulumi
  .output({ nodes, k0sctrl })
  //             ^ declare _all_ of the inputs to our apply function
  .apply(({ nodes, k0sctrl }) => ({
    spec: nodes.map((n) => ({
      kind: k0sctrl.role,
      // consuming it here
      role: n.role,
    })),
  }));

k0sConfig2.apply((cfg) => pulumi.log.info(JSON.stringify(cfg)));