[docs] enabling decorators: metro complains about loose option

[rhoehener]

I tried to follow https://mobx.js.org/installation.html and https://mobx.js.org/enabling-decorators.html to the letter, but now the metro bundler tells me this:

transform[stderr]: [proposal-class-properties]: You are using the "loose: true" option and you are explicitly setting a value for the "setPublicClassFields" assumption. The "loose" option can cause incompatibilities with the other class features plugins, so it's recommended that you replace it with the following top-level option:
transform[stderr]: "assumptions": {
transform[stderr]: "setPublicClassFields": true,
transform[stderr]: "privateFieldsAsProperties": true
transform[stderr]: }

is that loose setting still required, what should I do? could you please update the docs?

[mweststrate]

The docs mention explicitly that it should be loose: false, not true

…

On Tue, 8 Jun 2021, 21:55 Reto Höhener, ***@***.***> wrote: I tried to follow https://mobx.js.org/installation.html and https://mobx.js.org/enabling-decorators.html to the letter, but now the metro bundler tells me this: transform[stderr]: [proposal-class-properties]: You are using the "loose: true" option and you are explicitly setting a value for the "setPublicClassFields" assumption. The "loose" option can cause incompatibilities with the other class features plugins, so it's recommended that you replace it with the following top-level option: transform[stderr]: "assumptions": { transform[stderr]: "setPublicClassFields": true, transform[stderr]: "privateFieldsAsProperties": true transform[stderr]: } is that loose setting still required, what should I do? could you please update the docs? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2970>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAN4NBHZ3GACTAWO56EOPV3TRZ7TZANCNFSM46KW3PGQ> .

[rhoehener]

yes, and I have it set to false, but am still getting this message.

my babel.config.js:

module.exports = function(api) {
  api.cache(true);
  return {
    presets: ['babel-preset-expo'],
    // https://mobx.js.org/enabling-decorators.html
    "assumptions": {
      "setPublicClassFields": true,
      "privateFieldsAsProperties": true,
    },
    "plugins": [
      ["@babel/plugin-proposal-decorators", { "legacy": true }],
      ["@babel/plugin-proposal-class-properties", { "loose": false }]
      // In contrast to MobX 4/5, "loose" must be false!    ^
    ]
  };
};

[rhoehener]

if I remove the assumptions, the message goes away

[rhoehener]

I added that because of https://babeljs.io/docs/en/babel-plugin-proposal-decorators#note-compatibility-with-babelplugin-proposal-class-properties

[mweststrate]

Never saw the assumptions concept before, probably something that was added recently to Babel, but no idea what it means :).

[rhoehener]

Ok thank you for your quick feedback. I will ignore the babel docs about assumptions for now, and not set any.