TSC Crash: Javascript Object assignment

[terrance00]

TypeScript Version: 3.4.5

Search Terms:
tsc crash for .js where curly bracket object assignment is used in conjunction with OR assignment

Code
tsconfig:

..."allowJs" : true...

simple-js-file.js:

var NameSpace = NameSpace || { Shared: {} }; //DOES NOT WORK

Equivalent works:

var NameSpace = NameSpace || {};
NameSpace.Shared = {}; // WORKS

Expected behavior:
Typescript to compile the .js file to the out folder (Like the second example)

Actual behavior:

tsc : C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:72970
At line:1 char:1
+ tsc
+ ~~~
    + CategoryInfo          : NotSpecified: (C:\Users\TJevon...ib\tsc.js:72970:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError
 
                throw e;
                ^

RangeError: Maximum call stack size exceeded
    at checkPropertyAccessExpression (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:41094:47)
    at checkExpressionWorker (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:44380:28)
    at checkExpression (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:44317:38)
    at checkTruthinessExpression (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:46358:24)
    at checkBinaryLikeExpression (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:43762:28)
    at checkBinaryExpression (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:43753:20)
    at checkExpressionWorker (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:44420:28)
    at checkExpression (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:44317:38)
    at checkExpressionCached (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:44106:38)
    at getInitializerTypeFromAssignmentDeclaration (C:\Users\TJevon\AppData\Roaming\npm\node_modules\typescript\lib\tsc.js:29597:97)

Playground Link:

Related Issues:

[sandersn]

@terrance00 I tried this program:

var ns = ns || { shared: {} }

with this command line:

tsc --allowjs --noemit test.js
# and
tsc --allowjs --outdir out test.js

And didn't get a crash on any version of TS 2.2-3.6. Can you share your tsconfig that has the crash?

[terrance00]

@sandersn

Sorry, It seems to be when you actually use that anonymous object "shared", and also - you have to go one level deeper:

Just tested this snippet:

var ns = ns || { shared: {} };

ns.next = ns.next || {
    shared: {}
};

ns.next.shared.mymethod = function () {
    return "mystring";
};

[sandersn]

Thanks, that's it!

[sandersn]

Crashes from 3.3 onward.