Long time to save

[MIGUELez11]

Issue Type: Performance Issue

1. Install eslint and prettier extension
2. Enable format on save
3. Make a change on a .js file
4. Save the file

VS Code will take a VERY long time to format the file, i've done a extension bisect and indentified this extension as the problem.

Extension version: 1.20.0
VS Code version: Code 1.57.1 (Universal) (507ce72a4466fbb27b715c3722558bb15afa9f48, 2021-06-17T13:28:32.912Z)
OS version: Darwin x64 20.3.0
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz (12 x 2600)
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	9, 6, 5
Memory (System)	16.00GB (1.41GB free)
Process Argv	--crash-reporter-id 9d1c4122-332d-4170-bae7-c2a100218c94
Screen Reader	no
VM	0%

Process Info

CPU %	Mem MB	   PID	Process
   21	   115	   414	code main
   10	    82	   582	   gpu-process
    0	    16	   584	   utility
    0	   164	   586	   window (dependencies.js — test)
    0	     0	   825	     watcherService
    0	   180	  1074	     extensionHost
    0	     0	  1121	       electron_node tsserver.js 
    0	    16	  1123	       electron_node tsserver.js 
    0	     0	  1148	         electron_node typingsInstaller.js typesMap.js 
    0	     0	  1126	       electron_node index.js 
    0	     0	  1136	       electron_node server.js 
    0	     0	  1250	       electron_node eslintServer.js 
    0	    16	 20639	       /Applications/Visual Studio Code.app/Contents/Frameworks/Code Helper (Renderer).app/Contents/MacOS/Code Helper (Renderer) /Applications/Visual Studio Code.app/Contents/Resources/app/extensions/json-language-features/server/dist/node/jsonServerMain --node-ipc --clientProcessId=1074
    5	   164	   821	   shared-process
    0	    16	   824	     ptyHost
    0	     0	 48222	       /bin/zsh -l
    0	     0	 63195	     /bin/ps -ax -o pid=,ppid=,pcpu=,pmem=,command=
    2	    66	 63109	   window (Issue Reporter)
   17	   246	 63110	   window (knex.js — project)
   70	   279	 63111	     extensionHost
  102	   115	 63135	       electron_node tsserver.js 
  120	   115	 63136	       electron_node tsserver.js 
    2	    66	 63165	         electron_node typingsInstaller.js typesMap.js 
   53	    66	 63172	           npm install types-registry@latest
   66	    66	 63141	       electron_node server.js 
    0	     0	 63193	       (git)
    0	    49	 63112	     watcherService
    0	    33	 63147	     searchService

Workspace Info

|  Window (knex.js — project)
|  Window (dependencies.js — test)
|    Folder (test): 8 files
|      File types: js(3) nvmrc(1) json(1) lock(1)
|      Conf files: package.json(1)
|    Folder (project): 2471 files
|      File types: js(412) gz(65) json(54) lock(10) md(6) log(6) gitignore(4)
|                  env(4) css(3) ico(2)
|      Conf files: package.json(36) jsconfig.json(2);

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