typescript --allowJs too slow

[viktor-nikolaev]

TypeScript Version:

1.8.9

tsconfig.json

{
 "compilerOptions": {
 "target": "es5",
 "module": "amd",
 "noEmitOnError": true,
 "allowJs": true
 },
 "exclude": [
 "node_modules",
 "bower_components"
 ]
}

gulp task

var ts = require("gulp-typescript"),

var tsProject = ts.createProject("tsconfig.json", {
 noExternalResolve: true,
 typescript: require("typescript")
});

gulp.task("scripts", function() {
 return gulp.src(paths.devroot.ts)
 .pipe(ts(tsProject))
 .pipe(gulp.dest(paths.webroot.app));
});

gulp.task("watch", ["scripts"], function() {
 gulp.watch(paths.devroot.ts, ["scripts"]);
})

When I run the task with --allowJs set to true, it takes about 10seconds to build my project. Moreover it takes 10 seconds after any change in my files, ie it is not incrementaly.

When --allowJs is disabled, it takes about 1 second to build the whole project, and 100ms to build incrementally.

[mhegazy]

can you run tsc --diagnistics --listFiles with and without --allowJs and share the output?

[viktor-nikolaev]

Mohamed Hegazy (@mhegazy) , i ran it in a working pc, that a bit faster.
Actually, the main problem is with "-watch".

diag.allowJs.txt
diag.disallowJs.txt

diag.allowJs.watch.txt
diag.disallowJs.watch.txt

[mhegazy]

in the allowJS case, you are pulling in many more files (244 vs. 50). we are spending 2 more seconds in additional IO (reading the extra files, and writing their output) and 2 more seconds in type checking them see below.

without --allowJs

Files: 244
Lines: 54431
Nodes: 260098
Identifiers: 88870
Symbols: 7629718
Types: 11834
Memory used: 143379K
I/O read: 0.06s
I/O write: 1.99s
Parse time: 0.86s
Bind time: 0.40s
Check time: 2.17s
Emit time: 2.63s
Total time: 6.07s

No --allowJs

Files: 50
Lines: 24110
Nodes: 97627
Identifiers: 37579
Symbols: 1158822
Types: 6640
Memory used: 69853K
I/O read: 0.01s
I/O write: 0.07s
Parse time: 0.32s
Bind time: 0.26s
Check time: 0.78s
Emit time: 0.21s
Total time: 1.57s

The question is do you intend to include these files in your compilation? if no, then you should add App_Scripts to your exclude in tsconfig.json.