draber06

function changeLetterCase(str, letterCase, firstLetterReversed) {
    if (typeof str !== "string") {
        throw Error(`First parameter - ${typeof str} but must be string`);
    }

    if (letterCase != "upper" && letterCase != "lower") {
        throw Error(
            `Invalid parameter - letterCase: "${letterCase}". Two valid options: lower and upper`
        );
    }

draber06

var gulp = require("gulp"),
    streamqueue = require("streamqueue"),
    less = require("gulp-less"),
    autoprefixer = require("gulp-autoprefixer"),
    minifyCss = require("gulp-minify-css"),
    concat = require("gulp-concat"),
    uglify = require("gulp-uglify"),
    rename = require("gulp-rename"),
    combine = require("stream-combiner2"),
    es = require("event-stream"),