javascript - How to cope with ISO 8859-1 in gulp? -

i have existing site using iso 8859-1 cannot change utf-8. when use script, accent characters broken. how can tell gulp take account iso 8859-1 :

var gulp = require('gulp');   var inject = require('gulp-inject-string');  gulp.task('default', function(){     gulp.src('index.html')         .pipe(inject.before('</body>', '<script src="myscript.js"></script>\n'))         .pipe(gulp.dest('./test'));     console.log('myscript.js injected'); });