Compile sass files with ~

gulpfile.js

const path = require('path');

const gulp = require('gulp');
const sass = require('gulp-sass')(require('sass'));


// An importer that redirects relative URLs starting with "~" to
// `node_modules`.
function packageImporter(url) {

    // If the doesn't start with ~, return it as is.
    if (!url.startsWith('~')) {
        return null;
    }

    const nodeModules = path.resolve('./node_modules');

    // Create a new url to the correct location
    const file = path.resolve(
        nodeModules,
        url.slice(1)
    );

    return { file };
}

gulp.task('sass', function () {
    return gulp.src('./sass/**/*.scss')
        .pipe(sass({ importer: [packageImporter]}).on('error', sass.logError))
        .pipe(gulp.dest('./wwwroot/css'));
});