javascript optional chain completions

[lc150303]

Issue Type: Bug

After disable the javascript.suggest.includeAutomaticOptionalChainCompletions, and have an object A with declared type { B?: {C: 0} }. when I typed A.B.C, it will be auto replaced by A.B?.C, but in js file the '?.' operator should not exist.

VS Code version: Code 1.45.0 (d69a79b, 2020-05-07T16:18:48.860Z)
OS version: Windows_NT x64 10.0.18363

System Info

Item	Value
CPUs	Intel(R) Core(TM) i5-8265U CPU @ 1.60GHz (8 x 1800)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off protected_video_decode: enabled rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled viz_display_compositor: enabled_on viz_hit_test_surface_layer: disabled_off_ok webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	7.81GB (1.76GB free)
Process Argv
Screen Reader	no
VM	67%

Extensions: none

[mjbvz]

Please share a complete code example

[lc150303]

I have a jsconfig.json with

{  
    "include": [  
        "*"  
    ],  
    "compilerOptions": {  
        "checkJs": true,  
        "strict": true,  
    }  
}

and the setting is "javascript.suggest.includeAutomaticOptionalChainCompletions": false, and the code is

/**
 * @type {{b?:{c:number}}}
 */
let a = { b: { c: 7 } };
a.b?.c;

the '?' was inserted after i typed a.b.c;.

[lc150303]

Please share a complete code example
@mjbvz
as above

[mjbvz]

Thanks. Opened microsoft/TypeScript#38487 to track upstream