tsc --showConfig throws error when paths compilerOptions is supplied

[locorocorolling]

TypeScript Version: 3.2.1, 3.3.0-dev.20181204

Search Terms:

• --showConfig

Code

Running tsc on any tsconfig.json that has paths in compilerOptions
Example tsconfig.json:

{
  "compilerOptions": {
    "allowJs": true,
    "outDir": "./lib",
    "esModuleInterop": true,
    "module": "commonjs",
    "moduleResolution": "node",
    "target": "ES2017",
    "sourceMap": true,
    "baseUrl": ".",
    "paths": {
      "@root/*": ["./*"],
      "@configs/*": ["src/configs/*"],
      "@common/*": ["src/common/*"],
      "*": [
        "node_modules/*",
        "src/types/*"
      ]
    },
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "resolveJsonModule": true
  },
  "include": [
    "./src/**/*"
  ]
}

Expected behavior:
command-line prints out the effective tsconfig.json

Actual behavior:
this error occured:

TypeError: map.entries is not a function
    at Object.forEachEntry (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:6037:28)
    at getNameOfCompilerOptionValue (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:20125:19)
    at _loop_3 (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:20157:46)
    at serializeCompilerOptions (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:20164:13)
    at Object.convertToTSConfig (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:20076:25)
    at Object.executeCommandLine (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:75680:48)
    at Object.<anonymous> (C:\Users\loco\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:75900:4)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)

Upon inspecting into tsc.js, realised that function getCustomTypeMapOfCommandLineOption(optionDefinition) was having this behaviour:

    function getCustomTypeMapOfCommandLineOption(optionDefinition) {
        if (optionDefinition.type === "string" || optionDefinition.type === "number" || optionDefinition.type === "boolean") {
            return undefined;
        }
        else if (optionDefinition.type === "list") {
            return getCustomTypeMapOfCommandLineOption(optionDefinition.element);
        }
        else {
            return optionDefinition.type;
        }
    }

im prospecting that paths optionDefinition, which has a type of 'object', should not have a customTypeMap.
What a customTypeMap does is it maps the string value backs to a numeric value for use later?
Here's a sample for the 'target' options:

{ name: 'target',
  shortName: 't',
  type:
   Map {
     'es3' => 0,
     'es5' => 1,
     'es6' => 2,
     'es2015' => 2,
     'es2016' => 3,
     'es2017' => 4,
     'es2018' => 5,
     'esnext' => 6 },
  // ...
}

With that, i tried modifying function getCustomTypeMapOfCommandLineOption(optionDefinition) to return undefined for optionDefinition.type === "object" and it stops throwing the error:

    function getCustomTypeMapOfCommandLineOption(optionDefinition) {
        console.log(optionDefinition)
        console.log(`optionDefinition.type: ${optionDefinition.type}`)
        if (optionDefinition.type === "string" || optionDefinition.type === "number" || optionDefinition.type === "boolean") {
            return undefined;
        }
        else if (optionDefinition.type === "list") {
            return getCustomTypeMapOfCommandLineOption(optionDefinition.element);
        }
        else if (optionDefinition.type === "object") {
            return undefined;
        }
        else {
            return optionDefinition.type;
        }
    }

but im unsure if this is the intended behaviour.

Being a first-timer in open-source, would like some guidance along above and hopefully i can make a pull request for this?

*P.S. thanks for the patience for reading through! pardon for the Bad English 😂

[locorocorolling]

whoaaaa, thanks for the fix!