files-exist

This simple tool accepts an array of filenames with or without globbing wildcards and returns an identical array if all the filenames point to existing files on the file system.

Basic usage:

var filesExist = require('files-exist'),
files = filesExist(['package.json', 'node_modules/express/lib/express.js']);

Usage in unit testing

You can use files-existin your unit tests. Simply pass an array of files you want to exist and either check for errors or disable them and compare the array returned.

var chai = require('chai'),
filesExist = require('files-exist');

describe('images', function() {
  it('should contain at least one .png file', function() {
    var fileArray = ['images/*.png'];

    // Method one: pass a bound call and check for thrown errors
    chai.expect(filesExist.bind(filesExist, fileArray, { checkGlobs: true })).to.not.throw(Error);

    // Method two: suppress errors and check the returned results
    var results = filesExist(fileArray, { checkGlobs: true, throwOnMissing: false });
    chai.expect('images/*.png' in results).to.not.equal(false);
  });
});

Usage in build process

Use files-exist around your gulp.src() source files to notice when a soft dependency is broken. This can help you to spot newly added bower components that haven't been installed on your local machine yet.

var jsLibs = [
    sourcePath + '/vendor/jquery/dist/jquery.js',
    sourcePath + '/vendor/jquery.stellar/jquery.stellar.min.js',
    sourcePath + '/vendor/autofill-event/src/autofill-event.js',
    sourcePath + '/vendor/js-cookie/src/js.cookie.js',
    sourcePath + '/vendor/modernizr/modernizr.js',
    sourcePath + '/vendor/lodash/lodash.js'
];

gulp.task('build:js', function() {
  return gulp.src(filesExist(jsLibs, { exceptionMessage: 'Please run `bower install` to install missing library' }))
  .pipe(gulp.dest(outputPath + '/js'));
});

Options

checkGlobs

By default, files-exist doesn't check whether globs match any files. Set this to true to enable glob evaluation.

throwOnMissing

Set this to false if you don't want files-exist to throw any exceptions when missing files are encountered. Note that you'll need to check the returned array yourself in this case, as it will be returned without the missing files.

exceptionClass

Set the name of the exception class you want to use for the error message. Defaults to Error.

exceptionMessage

Customize the message of the exception. The name of the first missing file encountered will be appended.