[BUG] package.json#/config/*: Array changed behaviour to joining items with double new-line

[askirmas]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

package.json

{
"config": {
    "array": [
      "item1",
      "item2", "item3"
    ]
}}

process.env

{
  "npm_package_config_array": "item1\n\nitem2\n\nitem3"
}

Expected Behavior

process.env (Like it was at v6):

{
  "npm_package_config_array_0": "item1",
  "npm_package_config_array_1": "item2",
  "npm_package_config_array_2": "item3"
}

Steps To Reproduce

1. In this environment...
2. Clone bug repo - https://github.com/askirmas/npm7-bug-package_config/
3. Change npm version to 7
4. Run npm start
5. See error...

$ npm start 

> npm-bug-config@1.0.0 start
> node index.js

node:assert:123
throw new AssertionError(obj);
^

AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
+ actual - expected

{
+   npm_package_config_array: 'item1\n\nitem2\n\nitem3'
-   npm_package_config_array_0: 'item1',
-   npm_package_config_array_1: 'item2',
-   npm_package_config_array_2: 'item3'
}
  at Object.<anonymous> (/Users/kirmasy/code/npm-bug-config/index.js:7:1)
  at Module._compile (node:internal/modules/cjs/loader:1101:14)
  at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
  at Module.load (node:internal/modules/cjs/loader:981:32)
  at Function.Module._load (node:internal/modules/cjs/loader:822:12)
  at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:79:12)
  at node:internal/main/run_main_module:17:47 {
generatedMessage: true,
code: 'ERR_ASSERTION',
actual: { npm_package_config_array: 'item1\n\nitem2\n\nitem3' },
expected: {
  npm_package_config_array_0: 'item1',
  npm_package_config_array_1: 'item2',
  npm_package_config_array_2: 'item3'
},
operator: 'deepStrictEqual'
}

Environment

• OS: MacOS 11.5.2
• Node: 16.9.1
• npm: 7.21.1

[askirmas]

Same for npm v7.24.0

Nothing in docs https://docs.npmjs.com/cli/v7/configuring-npm/package-json#config

[siemhesda]

Hi @askirmas, After looking deeply into this issue here's a few things I found out...

Findings

The v7 changes to the config have actually been mentioned on the release/v7 changelog under the All Lifecycle Scripts section.

The section references RFC 21 (Reduce the environment variables provided to lifecycle scripts) which talks about the changes and the motivation behind them.

Workaround

For your case, you can achieve the config you are trying to by having the values as suggested below:

1. Previously:

{
  "config": {
    "array": ["item1", "item2", "item3"]
  }
}

process.env

{
  "npm_package_config_array": "item1\n\nitem2\n\nitem3"
}

2. Equivalent (solution)

{
  "config": {
    "array": {
      "0": "item1",
      "1": "item2",
      "2": "item3"
    }
  }
}

process.env (desired)

{
  "npm_package_config_array_0": "item1",
  "npm_package_config_array_1": "item2",
  "npm_package_config_array_2": "item3"
}

Progress

There's however need to have these changes reflected on the documentation (still exploring the justification for the change), or revert the part that causes the double new-line. I'm currently actively working on this issue and these are currently in progress.