const previousChapter = chapters => {
let previous = currentChapterIndex(chapters) - 1
if (previous <= 0) {
previous = 0
}
return chapters.map(setActiveByIndex(previous))
}
[UPDATE_CHAPTER]: (state, { payload }) => {
const chapters = state.list.map(setActiveByPlaytime(payload))
if (currentChapterIndex(chapters) === -1) {
return state
}
return generateState(chapters)
},
const nextChapter = chapters => {
let next = currentChapterIndex(chapters) + 1
if (next >= chapters.length - 1) {
next = chapters.length - 1
}
return chapters.map(setActiveByIndex(next))
}