gulp-contains 
Throws an error or calls a callback if a given string is found in a file.Useful for dumb quality checking.
Install
$ npm install --save-dev gulp-containsUsage
The following code will throw an error if "../nodemodules" is found in any Sass or SCSS file.var gulp = require('gulp');
var contains = require('gulp-contains');
gulp.task('default', function () {
gulp.src('./src/**/*.{sass, scss}')
.pipe(contains('../node_modules'));
});The contains function accepts a string, a regular expression or an array of either (any of which, when matched, will cause an error to be thrown).
You can also specify a callback function, in which you can handle the error yourself or choose to completely ignore it:
var gulp = require('gulp');
var contains = require('gulp-contains');
gulp.task('default', function () {
gulp.src('./src/**/*.{sass, scss}')
.pipe(contains({
search: '../node_modules',
onFound: function (string, file, cb) {
// string is the string that was found
// file is the vinyl file object
// cb is the through2 callback
// return false to continue the stream
}
}));
});