Gulp is nice, but I don't like the fact that there's no easy way to confirm that src found at least one file.
This package adds srcN(glob, min=0, max=Infinity, isError=true) to the gulp package. The glob argument is passed to gulp.src. A stream reader is attached to the resulting stream. This reader counts the number of files on the stream (objects, technically) and, just before the stream closes, verifies that the number of objects is between min and max (inclusive). If the number of files read is not between min and max, either a note is displayed on the console, if isError is false, or an error is added to the stream.
const gulp = require('gulp')
require('gulp-validated-src')(gulp)
//This example wants to see at least 1 file and the glob won't
//find one. srcN will throw an error onto the stream. This
//is the most common use case
gulp.task('copy exactly one file', function () {
return gulp.srcN('find 0 files', 1)
.pipe(gulp.dest('target/'))
})
The repository for this project is available at https://github.com/ze6ke/gulp-validated-src.
This library is available under the MIT license.