REPL, -e, and piped stdin globals are wrong: ,missing exports, module, etc.

[cspotcode]

Expected Behavior

ts-node --interactive -e "<expression>" should behave the same as node --interactive -e "<expression>"

-e should be evaluated with exports, etc.

Actual Behavior

exports is not defined during the evaluation of a -e expression.

Steps to reproduce the problem / Minimal reproduction

ts-node --interactive -e "console.log(exports, __filename)"
node --interactive -e "console.log(exports, __filename)"

Notes

Looks like a blind spot in our REPL logic in bin.ts We should check that all the module-specific variables, exports, __filename, etc match nodejs.

[cspotcode]

Seems this bit of code, which only runs when you call start(), should actually be run earlier in some of our -e codepaths.
https://github.com/TypeStrong/ts-node/blob/main/src/repl.ts#L263-L268

[cspotcode]

Did some more research here.

node --interactive REPL uses the global object as the REPL's scope. We opt-in to the same via the API.

node -e '< expression >' gets access to a bunch of variables added to the global object.
So does REPL code.

I did a test logging the set of fields on global which are added by calling new REPLServer()

[
  'module',      'require',             'assert',
  'async_hooks', 'buffer',              'child_process',
  'cluster',     'constants',           'crypto',
  'dgram',       'diagnostics_channel', 'dns',
  'domain',      'events',              'fs',
  'http',        'http2',               'https',
  'inspector',   'net',                 'os',
  'path',        'perf_hooks',          'punycode',
  'querystring', 'readline',            'repl',
  'stream',      'string_decoder',      'sys',
  'timers',      'tls',                 'trace_events',
  'tty',         'url',                 'util',
  'v8',          'vm',                  'worker_threads',
  'zlib',        '_',                   '_error'
]

The modules like fs are getters, presumably for performance.

global.__filename and global.__dirname are set for -e or -p, but only stick around on the global object if you do node -p "" -i

__filename is [eval] for -e, [stdin] for piped input.

stdin and -e global.module, .exports, .require, .__filename, .__dirname set.

new REPLServer() only sets .module, .require, but includes _ and _error.

console is not overwritten. I thought it might have been to redirect console.log() to the stdin and stdout passed to the REPL, but no.

Looks like we need to do these things:

• call new REPLServer() before any sort of -e, -p, -i, or piped stdin
• set __filename and __dirname only in certain codepaths
• choose between [eval] and [stdin] for __filename
• Continue to always set exports because TS emitted code requires it
• update REPL API to let you opt-out of using the global object as context
• ensure REPL API exposes .context
• Consider adding call to REPL API to create REPLServer without starting it

[cspotcode]

Also must be sure module.paths matches in all cases. Appears to differ between -p and repl.

❯ node -p '[module.id, module.paths]' -i
Welcome to Node.js v16.1.0.
Type ".help" for more information.
> [
  '[eval]',
  [
    '/d/Personal-dev/@TypeStrong/ts-node/node_modules',
    '/d/Personal-dev/@TypeStrong/node_modules',
    '/d/Personal-dev/node_modules',
    '/d/node_modules',
    '/node_modules'
  ]
]
> [[module.id, module.paths]
... [module.id, module.paths]
...
> [module.id, module.paths]
[
  '<repl>',
  [
    '/d/Personal-dev/@TypeStrong/ts-node/repl/node_modules',
    '/d/Personal-dev/@TypeStrong/ts-node/node_modules',
    '/d/Personal-dev/@TypeStrong/node_modules',
    '/d/Personal-dev/node_modules',
    '/d/node_modules',
    '/node_modules',
    '/home/cspotcode/.node_modules',
    '/home/cspotcode/.node_libraries',
    '/home/cspotcode/n/lib/node'
  ]
]
>

[cspotcode]

Discrepancy between:

node -p 'process.argv' ./subdir/index.ts
ts-node -p -e 'process.argv' ./subdir/index.ts

node treats the positional as an argv string, does NOT attempt to execute it.

ts-node breaks:

• attempts to resolve it to a file; fails if doesn't exist
• uses the path to set the location of internal EvalState
• TS compiler complains if it points to a file that should not be compiled

[cspotcode]

Our repl does process.exit(). We should make the REPL API raise an error somehow, and call process.exit() in response to that error in our bin.ts.

[cspotcode]

Renamed to capture scope of this ticket.