Gulp TypeError: Arguments to path.join must be strings

With the syntax changes in gulp-ruby-sass starting from 1.0.0-alpha, you’ll need to use gulp-ruby-sass() instead of gulp.src() to compile your Sass from a file or directory.

If you try to use the original syntax with newer or latest versions, you may encounter the following error:

TypeError: Arguments to path.join must be strings

For example, the original syntax in 0.7.x and earlier using gulp.src(), now deprecated:

var gulp = require('gulp');
var sass = require('gulp-ruby-sass');

// gulp-ruby-sass: 0.7.1
gulp.task('sass', function() {
    return gulp.src('path/to/scss')
        .pipe(sass({ style: 'expanded' }))
        .pipe(gulp.dest('path/to/css'));
});

The new syntax introduced in 1.x using gulp-ruby-sass() as a gulp source adapter:

// gulp-ruby-sass: 1.x
gulp.task('sass', function() {
    return sass('path/to/scss', { style: 'expanded' })
        .pipe(gulp.dest('path/to/css'));
});

Notice the difference in the first line of the return statement.

Also keep in mind, as of this writing when using gulp-ruby-sass 1.0.0-alpha, globs are not supported yet.