New has() method that replaces arr.indexOf where applicable

Left out the occasions where indexOf was checking a particular index (instead of just checking wether an index exists or not)

lib/util.js

@@ -67,4 +67,13 @@ exports.formatDuration = function (seconds) {
  * @param {String} str
  * @return {Boolean}
  */
-exports.isString = str => typeof str === "string";
+exports.isString = str => typeof str === "string";
+
+/**
+ * Checks arr contains value
+ *
+ * @param {Array} arr
+ * @param {string|number} arr
+ * @return {Boolean}
+ */
+exports.has = (arr, value) => arr && arr.indexOf(value) > -1;

lib/youtube-dl.js

@@ -70,7 +70,7 @@ function youtubeDl(urls, args, options, callback) {
  return call(video, args1, cleanupOpt, options, callback);
  }
 
- if (isDebug.test(stderr) && args.indexOf('--verbose') > -1) {
+ if (isDebug.test(stderr) && util.has(args, "--verbose")) {
  console.log('\n' + stderr);
  } else if (isWarning.test(stderr)) {
  console.warn(stderr);
@@ -308,7 +308,7 @@ ytdl.getInfo = function getInfo(url, args, options, callback) {
  args = [];
  }
  const defaultArgs = ['--dump-json'];
- if (!args || args.indexOf('-f') < 0 && args.indexOf('--format') < 0 &&
+ if (!args || !util.has(args, "-f") && !util.has(args, "--format") &&
  args.every(function (a) {
  return a.indexOf('--format=') !== 0;
  })) {
@@ -322,7 +322,7 @@ ytdl.getInfo = function getInfo(url, args, options, callback) {
 
  // If using the "-g" or "--get-url" flag youtube-dl will return just a string (the URL to the video) which messes up the parsing
  // This fixes this behaviour
- if (args && (args.indexOf("-g") > -1 || args.indexOf("--get-url") > -1))
+ if (util.has(args, "-g") || util.has(args, "--get-url"))
  if (Array.isArray(data) && data.length >= 2) data.splice(0, 1);
 
 
@@ -414,7 +414,7 @@ ytdl.getThumbs = function getThumbs(url, options, callback) {
  for (let i = 0, len = data.length; i < len; i++) {
  const line = data[i];
  const info = 'Writing thumbnail to: ';
- if (line.indexOf(info) !== -1) {
+ if (util.has(line, info)) {
  files.push(line.slice(line.indexOf(info) + info.length));
  }
  }