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'use strict'
const { flattenGrouplike } = require('./playlist-utils')
function makeLoopingOrderedPlaylistPicker(grouplike) {
// Looping ordered playlist picker - this plays all the tracks in a group
// in order, while looping the same order forever.
const flatGroup = flattenGrouplike(grouplike)
let index = 0
return function() {
if (index >= flatGroup.items.length) {
index = 0
}
const picked = flatGroup.items[index]
index++
return picked
}
}
function makeNonLoopingOrderedPlaylistPicker(grouplike) {
// Ordered playlist picker - this plays all the tracks in a group in
// order, after flattening it.
const flatGroup = flattenGrouplike(grouplike)
let index = 0
return function() {
if (index < flatGroup.items.length) {
const picked = flatGroup.items[index]
index++
return picked
} else {
return null
}
}
}
function makeLoopingShufflePlaylistPicker(grouplike) {
// Shuffle playlist picker - this selects a random track at any index in
// the playlist, after flattening it.
const flatGroup = flattenGrouplike(grouplike)
return function() {
if (flatGroup.items.length) {
const index = Math.floor(Math.random() * flatGroup.items.length)
return flatGroup.items[index]
} else {
return null
}
}
}
function makeNonLoopingShufflePlaylistPicker(grouplike) {
// No-loop shuffle playlist picker - this takes a playlist and randomly
// shuffles the order of the items in it, then uses that as an "ordered"
// playlist (i.e. it plays all the items in it then stops).
const flatGroup = flattenGrouplike(grouplike)
const items = shuffleArray(flatGroup.items)
return function() {
if (items.length) {
return items.splice(0, 1)[0]
} else {
return null
}
}
}
function shuffleArray(array) {
// Shuffles the items in an array. Super-interesting post on how it works:
// https://bost.ocks.org/mike/shuffle/
const workingArray = array.slice(0)
let m = array.length
while (m) {
let i = Math.floor(Math.random() * m)
m--
// Stupid lol; avoids the need of a temporary variable!
Object.assign(workingArray, {
[m]: workingArray[i],
[i]: workingArray[m]
})
}
return workingArray
}
module.exports = {
makeLoopingOrderedPlaylistPicker,
makeNonLoopingOrderedPlaylistPicker,
makeLoopingShufflePlaylistPicker,
makeNonLoopingShufflePlaylistPicker,
byName: {
'order': makeNonLoopingOrderedPlaylistPicker,
'ordered': makeNonLoopingOrderedPlaylistPicker,
'order-loop': makeLoopingOrderedPlaylistPicker,
'ordered-loop': makeLoopingOrderedPlaylistPicker,
'order-noloop': makeNonLoopingOrderedPlaylistPicker,
'ordered-noloop': makeNonLoopingOrderedPlaylistPicker,
'order-no-loop': makeNonLoopingOrderedPlaylistPicker,
'ordered-no-loop': makeNonLoopingOrderedPlaylistPicker,
'shuffle': makeLoopingShufflePlaylistPicker,
'shuffle-loop': makeLoopingShufflePlaylistPicker,
'shuffle-noloop': makeNonLoopingShufflePlaylistPicker,
'shuffle-no-loop': makeNonLoopingShufflePlaylistPicker,
}
}
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