flow-runtime-cli doesn't output type aliases

[harrykao]

This is a:

• [ ] Bug Report
• [ ] Feature Request
• [X] Question
• [ ] Other

Which concerns:

• [X] flow-runtime
• [ ] babel-plugin-flow-runtime
• [ ] flow-runtime-validators
• [ ] flow-runtime-mobx
• [ ] flow-config-parser
• [ ] The documentation website

---

What is the current behaviour?

(This is similar to #69 but, TBH, I don't understand what the problem was and flow-runtime-cli didn't produce any output for me. If there are some docs that describe what's happening, please point me in the right direction.)

When running the following code:

import axios from 'axios';
import type {AxiosPromise} from 'axios';
    
const request: AxiosPromise<any> = axios.get('https://google.com/');

...this message is printed to the console:

flow-runtime: Failed to reveal unknown type in Temporal Dead Zone.

Can you help me understand what this means and what the right fix is?

---

What is the expected behaviour?

No message appears.

---

Which package versions are you using?

{
  "dependencies": {
    "axios": "^0.16.1",
    "babel-cli": "^6.24.1",
    "babel-plugin-flow-runtime": "^0.11.1",
    "babel-plugin-transform-decorators-legacy": "^1.3.4",
    "babel-preset-react": "^6.24.1",
    "babel-preset-stage-2": "^6.24.1",
    "flow-bin": "^0.47.0",
    "flow-runtime": "^0.12.0",
    "flow-runtime-cli": "^0.12.0",
    "flow-typed": "^2.1.2"
  }
}

[phpnode]

It happens because flow-runtime cannot resolve that type, are there any type definitions for AxiosPromise? If so flow-runtime-cli should be picking them up

[harrykao]

Thanks for the quick response. The type definition is installed from flow-typed. If I change the file like this:

// @flow

import axios from 'axios';
import type {AxiosPromise} from 'axios';

const request: AxiosPromise<any> = axios.get('https://google.com/');

request.then((response) => {
  console.log(response.DOES_NOT_EXIST);
});

Flow detects the error:

$ node_modules/.bin/flow
src/test.js:9
  9:   console.log(response.DOES_NOT_EXIST);
                            ^^^^^^^^^^^^^^ property `DOES_NOT_EXIST`. Property not found in
  9:   console.log(response.DOES_NOT_EXIST);
                   ^^^^^^^^ AxiosXHR


Found 1 error

But I still get the same console output when I run it:

$ node_modules/.bin/babel src/test.js | node
flow-runtime: Failed to reveal unknown type in Temporal Dead Zone.
undefined

And I get the same message with flow-runtime-cli:

$ ./node_modules/.bin/flow-runtime generate src
flow-runtime: Failed to reveal unknown type in Temporal Dead Zone.

[phpnode]

Need to figure out why flow-runtime-cli isn't picking it up, which version is coming from flow-typed? Presumably https://github.com/flowtype/flow-typed/tree/master/definitions/npm/axios_v0.16.x ?

It will be a while before I have time to look into this myself, but if you fancy digging into the details I'd gladly accept a PR.

[harrykao]

Okay, good to know that the correct behavior is for flow-runtime-cli to pick it up. I'll see if I can take a look in the next few days.

And yes, I installed the definitions for Axios 0.16.

[harrykao]

Oh, by the way, I think that "Failed to reveal unknown type in Temporal Dead Zone" error message is a red herring. It happens even when I run flow-runtime on an empty file. It seems to be related to runtime checks on flow-runtime itself when it's calling into minimist to parse the args.

[harrykao]

I'm not sure that I know enough to fix this. But I noticed that the AST for the Axios library definition has TypeAlias nodes for the declare type lines:

https://astexplorer.net/#/gist/8b8e67cb3d55ae731e26a03218a0611e/37c7cba991d91f865098ea1f97ff89964735ce75

And if I change this line:

https://github.com/codemix/flow-runtime/blob/acc4e3608008d17a4157521664068e99939912ff/packages/flow-runtime-cli/src/importAST.js#L63

To say || path.type === 'TypeAlias', then the flow-runtime command generates output. I don't know if this is the right fix though. Is this enough for you to go on?

[bradennapier]

My cli outputs absolutely nothing when i try even though I have tons of flow-typed files available.It also does not pick up the core libraries for things like react and the core js objects so I can't even use Promise or Iterator etc without errors