tsc -w is unacceptably slow

[oliverjanik]

I'm on windows. Typescript version installed via npm is 1.7.5. When I do tsc -w typescript watches for changes but its change detection is really slow. I takes about 10s before it notices I made a change and then recompiles.

What could be causing this?

Edit: Node 5.3.0

[Olgagr]

I have the same problem with 1.7.5 on Mac. In my case, it takes ~ 5 seconds before it notices that something changed.

[RyanCavanaugh]

What version of node are you using?

[Olgagr]

I'm using 5.2.0 but the same problem I had on 0.12.2. I have no problem withtsc -w in version 1.7.3.

[DanielRosenwasser]

Pinging @zhengbli and @vladima.

[DanielRosenwasser]

Just as a heads up everyone, you can go back to 1.7.3 with no user-facing issues. 1.7.5's only change was on file watching behavior which is what you're noticing.

[fergusg]

FWIW, I see same problem (except even slower ~ 20s delay) on Linux w/ node 4.0.0. Still slow with current snapshot 1.8.0-dev.20151222

[oliverjanik]

I tried 1.7.3 on 5.3.0/Win and it's only marginally better: 4-5s.

[deflexor]

Same issue on Linux with node 0.10. Delay is about 4-5 seconds. Tried 1.7.5 and 1.7.3 - same result.
Here is tsconfig.json:

{
    "compilerOptions": {
        "target": "ES5",
        "module": "system",
        "moduleResolution": "node",
        "sourceMap": true,
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "removeComments": false,
        "noImplicitAny": true,
        "outDir": "./app"
    },
    "exclude": [
        "node_modules"
    ]
}

[kamilmac]

Same 5s delay here (ver 1.7.5 and 1.5.3 before) on mac with following tsconfig:

{
  "compilerOptions": {
    "target": "es5",
    "module": "system",
    "moduleResolution": "node",
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false,
    "noImplicitAny": false
  },
  "exclude": [
    "node_modules"
  ]
}

[FlorianBELLAZOUZ]

Same issue
5 second delay
node v4.1.0 on windows.

tsconfig.json :

{
  "compilerOptions": {
    "target": "ES5",
    "module": "commonjs",
    "moduleResolution": "node",
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "removeComments": false
  },
  "exclude": [
    "node_modules",
    ".git"
  ]
}

[stefk]

Same issue on linux, node 5.1.0. Fixed with 1.7.3.

[realyze]

Same issue on Mac OS X 10.11. Downgrading to 1.7.3 helps partially - sometimes the watcher fires fast, most of the time there's a big delay.

[mhegazy]

PR #6026 should address this issue. We should have this in shortly. sorry for the delay.

[johnpapa]

Thanks for the status update @mhegazy

Looking forward for th fix. This explains a slowdown I have in my angular 2 app using lite-server

[asadsahi]

I am having slow reload with typescript 1.7+, works fine with typescript 1.6.

Anybody else?

[mhegazy]

@asadsahi this change was introduced between TS 1.7.3 and TS 1.7.5, if you are running into issues with TS 1.7.3 then it is a different issue.

[asadsahi]

I am having same issue with typescript 1.7.3.

[mhegazy]

@asadsahi that is a different issue then. can you provide more details? how many files do you have? can you share your configurations?

[oliverjanik]

I think it's still the same issue as many commenters pointed out. There's very little difference between 1.7.3 and 1.7.5 they're both slow compared to other watchers like gulp watch or webpack watch.

[zhengbli]

A fix was merged in master just now and will be published tomorrow via typescript@next on npm, so if anyone is willing to give it a shot it would be great. Thanks!

[mhegazy]

@oliverjanik, @asadsahi, @stefk, @realyze, @johnpapa, @deflexor, @FlorianBELLAZOUZ, @kamilmac, @fergusg and @Olgagr can you give typescript@next a try, and let us know if the issue has been resolved?

[fergusg]

@mhegazy It's certainly better but still slow with a ~7s lag (1.7.3 is <<1s)

Version 1.8.0-dev.20160114

[fergusg]

@zhengbli one reason for the still slightly slow change detection may be that tsc -w still seems to be watching ./node_modules dir, even though tsconfig.json has

    "exclude": [
        "node_modules"
    ]

i.e., when I touch a .ts file in node_modules, I get change detection.

[zhengbli]

Is the .ts file in your node_modules folder referenced by your file somewhere? If so it is supposed to be watched. I tried to put a random .ts file in the node_modules folder and didn't see changes were picked up. Can you confirm?

Also, it would be of great help if you can put the error log when the tsc -w is not working stably, or point me to a sample project that could lead to a repro. Thanks!

[fergusg]

@zhengbli

In my case @next gives an error not present in 1.7.3:

> tsc -p . --sourceRoot app

node_modules/angular2/src/facade/promise.d.ts(1,10): error TS2661: 
    Cannot re-export name that is not defined in the module.

That's what I used to generate the previously described problem:

$ touch node_modules/angular2/src/facade/promise.d.ts

This triggers the change detection. I'm not explicitly referencing that file anywhere.

I'll try to get a sample project together...

[fergusg]

@zhengbli

You could try https://github.com/fergusg/my-ng2-sandbox which is what I'm using. I'm slightly embarrassed to point you at that messy hack job (not intended for anyone but me) which is a learning pit for angular 2, but what the hell...

[mhegazy]

@fergusg this error is caused by the fix for #6323, I will send a fix for the angular package to address the issue.

[zhengbli]

@fergusg Thanks for the sample! Is this where the watching doesn't work consistently? I tried editing all .ts files in the app folder, and all changes were detected, so if there is a problem, it is not caused by the file name. Did you see the issue after a long session? How often do you see it stopped working?

[fergusg]

@zhengbli Sorry, I can't reproduce reliably :-(

I edit .ts files (Visual Studio Code FWIW) and mostly those changes are detected. But "from time to time" tsc -w just stops picking up those changes. Completely. Only restarting tsc -w fixes it.

[fergusg]

@zhengbli To answer your questions more explicitly:

Did you see the issue after a long session?
I saw it even after a minute or so with only 2 or 3 .ts saves

How often do you see it stopped working?
3 or 4 times in my recent session (2 hrs with constant saves)

[johnpapa]

I've run several tests and its very slow with TypeScript 1.7+. I wrote lite-server which runs browser-sync. If I run tsc with a watch and browser-sync, on typescript v 1.6 it takes about 2 seconds to reload the page when i have a 1s delay on browser sync. this is awesome.

If I run the same thing with typescript 1.7.5 or typescript@next, it takes 20+ seconds

you can repeat this by pulling the https://github.com/johnpapa/angular2-tour-of-heroes sample, npm i and run npm start from the command line.

UPDATE

if I use npm install typescript@next it is now working quickly. maybe a new rev since i last tried. here is what i have exactly

"typescript": "^1.8.0-dev.20160119"

[zhengbli]

@johnpapa a fix for the slowness in watching mode was merged in master last week, so the one in typescripe@next has the fix in.

[johnpapa]

i see 1.8 is in this repo, is it going to npm shortly too?

[mhegazy]

we are closing down on 1.8 bugs. we should have something out in the next few weeks. typescript@next now should be very close to the final 1.8 drop.

[johnpapa]

ok. i saw the version here https://github.com/Microsoft/TypeScript/blob/master/package.json#L5 and got excited and confused :)

[mhegazy]

:) we bump up the version in master once we ship to make sure that nighties have the correct version number.

[danieleds]

@fergusg I have the same issue:

node_modules/angular2/src/facade/promise.d.ts(1,10): error TS2661:
      Cannot re-export name that is not defined in the module.

Is it a bug in tsc or in Angular?

EDIT: might be related to #6323

[vladima]

this is the issue in angular, I think that the fix is already submitted

[squarewave24]

im on 1.8.10 and the problem continues on mac.
that same version on windows is instantaneous. in fact it's identical package.json file as i'm following the ng2 quick start template. for some reason on a mac the changes take 5-20s to be detected

  "dependencies": {
    "@angular/common":  "2.0.0-rc.1",
    "@angular/compiler":  "2.0.0-rc.1",
    "@angular/core":  "2.0.0-rc.1",
    "@angular/http":  "2.0.0-rc.1",
    "@angular/platform-browser":  "2.0.0-rc.1",
    "@angular/platform-browser-dynamic":  "2.0.0-rc.1",
    "@angular/router":  "2.0.0-rc.1",
    "@angular/router-deprecated":  "2.0.0-rc.1",
    "@angular/upgrade":  "2.0.0-rc.1",
    "systemjs": "0.19.27",
    "core-js": "^2.4.0",
    "reflect-metadata": "^0.1.3",
    "rxjs": "5.0.0-beta.6",
    "zone.js": "^0.6.12",
    "angular2-in-memory-web-api": "0.0.11",
    "bootstrap": "^3.3.6"
  },
  "devDependencies": {
    "concurrently": "^2.0.0",
    "lite-server": "^2.2.0",
    "typescript": "^1.8.10",
    "typings":"^1.0.4"
  }

[squarewave24]

@johnpapa running npm install typings@next screwed me up with this error typings/typings#554
fixed it by running typings install env~node -SG, but all this did not do anything for tsc change detection speed.

[squarewave24]

actually never mind, much faster now :)

[sumant30]

I am using Node Js ver 7.8.0 and file watcher is taking loads of time recognizing my file changes. My typescript ver is 2.2.1.

[zhengbli]

@sumant30 Can you share your tsconfig.json / OS / file system? You are using the tsc -w right?

[sumant30]

Os : windows 7 & file system : NTFS & You are using the tsc -w right? : Yes

And my tsconfig.json is below

{
"compilerOptions": {
"target": "es5",
"module": "commonjs",
"moduleResolution": "node",
"sourceMap": true,
"emitDecoratorMetadata": true,
"experimentalDecorators": true,
"removeComments": false,
"noImplicitAny": false,
"suppressImplicitAnyIndexErrors": true,
"typeRoots": [
"./node_modules/@types/"
]
},
"compileOnSave": true,
"exclude": [
"node_modules/",
"**/-aot.ts"
]
}