multiple gulp concat - not supported ?

[raDiesle]

Hi,

using

gulp.src("file.js")
.pipe(concat("file2.js"))
.pipe(concat("file3.js"))
.pipe(gulp.dest("file4.js"));

will not put all files into dest.
Is this expected ?
If true, why does it makes a difference when operating on streams ?

I know using gulp.src(["file.js", "file2.js", "file3.js", "file4.js"]) will fix it.

[yocontra]

What are you expecting to happen here?

[naeramarth7]

Behaviour of gulp-concat is correct. What your code actually does is renaming file.js to file4.js:

gulp.src("file.js")             // 1
.pipe(concat("file2.js"))       // 2
.pipe(concat("file3.js"))       // 3
.pipe(gulp.dest("file4.js"));   // 4

1. Put file.js only into the stream
2. Concat all vinyl files into a single file called file2.js - the only file in the stream is file.js so your actually just renaming it to file2.js
3. Concat all vinyl files into a single file called file3.js - same as in step 2
4. Write the vinyl files from stream to a file called file4.js

I know using gulp.src(["file.js", "file2.js", "file3.js", "file4.js"]) will fix it.

This will not just fix it, it is the correct way to use streams and gulp-concat.