Error: Cannot find module ' gulp-sass' - npm

Question

I'm having trouble getting gulp to read my modules.
Initially I had a working system.
I then upgraded to with NVM (I removed everything installed with Brew first)
Here's what I have now:
"node: v6.11.2"
"npm: 3.10.10"
"nvm"
and I have a gulpfile which used to work, but I also upgraded my modules, and I have installed locally in my project:
"gulp": "^3.9.1",
"gulp-pug": "^3.3.0",
"gulp-sass": "^3.1.0"
globally for this version of node I do have:
gulp-cli#1.4.0
jshint#2.9.5
npm#3.10.10
in a simple gulpfile running: gulp would work successfully, but introducing other modules is where I started getting issues.
In my gulpfile I have for example:
var gulp = require('gulp');
var sass = require(' gulp-sass'),
prefixer = require('gulp-autoprefixer'),
minifycss = require('gulp-clean-css'),
sourcemaps = require('gulp-sourcemaps'),
rename = require("gulp-rename");
gulp.task('sass', function () {
return gulp.src(src.sass)
.pipe(sourcemaps.init())
.pipe(sass())
.pipe(prefixer())
.pipe(gulp.dest(src.css))
.pipe(minifycss())
.pipe(rename({suffix: '.min'}))
.pipe(sourcemaps.write('/maps'))
.pipe(gulp.dest(src.css))
.pipe(connect.reload());
});
..locally running any command like gulp sass would produce:
Error: Cannot find module ' gulp-sass'
at Function.Module._resolveFilename (module.js:469:15)
at Function.Module._load (module.js:417:25)
at Module.require (module.js:497:17)
at require (internal/module.js:20:19)
at Object.<anonymous> (/Users/myusername/sites/projectname/gulpfile.js:25:12)
at Module._compile (module.js:570:32)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
I've removed the node_modules, removed the dependancies in package.json, reinstalled each local module

Answer 1

' gulp-sass' should be 'gulp-sass'

Answer 2

You are injecting a package with an additional space in the beginning of the package name. Remove the space and try it again.
var sass = require(' gulp-sass'),
should be
var sass = require('gulp-sass'),