'regeneratorRuntime is not defined'

[philipp-tailor]

As of #296, vue-cli-plugin-apollo is broken when using it in environments which don't include regenerator-runtime. The reason that this has gone mostly unnoticed (except for #386) seems to be that nearly everyone transpiles their bundles in ways which conceal the fact.

What causes the issue?

The usage of async/await in graphql-client/src/index.js.

The file is transpiled with build:graphql-client, which basically just uses @babel/preset-env. This preset includes IE11 and adds calls to regenerator-runtime, presuming that it's globally available.

Showcase:

• REPL of async function with default env preset: includes calls to the non-defined regeneratorRuntime.
• REPL of async function with default env preset minus IE11: does not include calls to regeneratorRuntime.

How to resolve the issue?

I am no expert on distributing packages nowadays. I see two simple possible ways to remove the issue:

• Install regeneratorRuntime and import it in graphql-client/src/index.js. The dist output is then able to run as distributed, even in IE11 (but probably bloated in size). Edit: it seems that another / the recommended option for a library would be to add @babel/plugin-transform-runtime to .babelrc. That would result in such output.
• Change the babel config to exclude IE11 as transpile target. The dist output would be able to run on its own, except for browsers not supporting async/await.
  One could also consider building / shipping two versions, one modern bundle output, and one maximum compatible commonjs output.

I am happy to open PRs in any of the directions described above.

[franciscolourenco]

This problem is reproducible when enabling --modern mode for example.

[johannespfrang]

Some time ago I've published vue-cli-plugin-apollo-without-regenerator-runtime to. Feel free to use/pin that.