????
Your IP : 216.73.216.64
const {isArray} = require('core-util-is')
const {sort} = require('array-timsort')
const {
SYMBOL_PREFIXES,
UNDEFINED,
symbol,
copy_comments,
swap_comments
} = require('./common')
const reverse_comments = array => {
const {length} = array
let i = 0
const max = length / 2
for (; i < max; i ++) {
swap_comments(array, i, length - i - 1)
}
}
const move_comment = (target, source, i, offset, remove) => {
copy_comments(target, source, i + offset, i, remove)
}
const move_comments = (
// `Array` target array
target,
// `Array` source array
source,
// `number` start index
start,
// `number` number of indexes to move
count,
// `number` offset to move
offset,
// `boolean` whether should remove the comments from source
remove
) => {
if (offset > 0) {
let i = count
// | count | offset |
// source: -------------
// target: -------------
// | remove |
// => remove === offset
// From [count - 1, 0]
while (i -- > 0) {
move_comment(target, source, start + i, offset, remove)
}
return
}
let i = 0
// | remove | count |
// -------------
// -------------
// | offset |
// From [0, count - 1]
while (i < count) {
const ii = i ++
move_comment(target, source, start + ii, offset, remove)
}
}
const remove_comments = (array, key) => {
SYMBOL_PREFIXES.forEach(prefix => {
const prop = symbol(prefix, key)
delete array[prop]
})
}
const get_mapped = (map, key) => {
let mapped = key
while (mapped in map) {
mapped = map[mapped]
}
return mapped
}
class CommentArray extends Array {
// - deleteCount + items.length
// We should avoid `splice(begin, deleteCount, ...items)`,
// because `splice(0, undefined)` is not equivalent to `splice(0)`,
// as well as:
// - slice
splice (...args) {
const {length} = this
const ret = super.splice(...args)
// #16
// If no element removed, we might still need to move comments,
// because splice could add new items
// if (!ret.length) {
// return ret
// }
// JavaScript syntax is silly
// eslint-disable-next-line prefer-const
let [begin, deleteCount, ...items] = args
if (begin < 0) {
begin += length
}
if (arguments.length === 1) {
deleteCount = length - begin
} else {
deleteCount = Math.min(length - begin, deleteCount)
}
const {
length: item_length
} = items
// itemsToDelete: -
// itemsToAdd: +
// | dc | count |
// =======-------------============
// =======++++++============
// | il |
const offset = item_length - deleteCount
const start = begin + deleteCount
const count = length - start
move_comments(this, this, start, count, offset, true)
return ret
}
slice (...args) {
const {length} = this
const array = super.slice(...args)
if (!array.length) {
return new CommentArray()
}
let [begin, before] = args
// Ref:
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/slice
if (before === UNDEFINED) {
before = length
} else if (before < 0) {
before += length
}
if (begin < 0) {
begin += length
} else if (begin === UNDEFINED) {
begin = 0
}
move_comments(array, this, begin, before - begin, - begin)
return array
}
unshift (...items) {
const {length} = this
const ret = super.unshift(...items)
const {
length: items_length
} = items
if (items_length > 0) {
move_comments(this, this, 0, length, items_length, true)
}
return ret
}
shift () {
const ret = super.shift()
const {length} = this
remove_comments(this, 0)
move_comments(this, this, 1, length, - 1, true)
return ret
}
reverse () {
super.reverse()
reverse_comments(this)
return this
}
pop () {
const ret = super.pop()
// Removes comments
remove_comments(this, this.length)
return ret
}
concat (...items) {
let {length} = this
const ret = super.concat(...items)
if (!items.length) {
return ret
}
move_comments(ret, this, 0, this.length, 0)
items.forEach(item => {
const prev = length
length += isArray(item)
? item.length
: 1
if (!(item instanceof CommentArray)) {
return
}
move_comments(ret, item, 0, item.length, prev)
})
return ret
}
sort (...args) {
const result = sort(
this,
// Make sure there is no more than one argument
...args.slice(0, 1)
)
// For example,
// if we sort ['b', 'd', 'c', 'a'],
// then `result` will be [3, 0, 2, 1], and the array is ['a', 'b', 'c', 'd']
// First, we swap index 0 (b) and index 3 (a), then the array comments are
// ['a.comments', 'd.comments', 'c.comments', 'b.comments']
// index 0 is finalized
// index 3 is actually mapped to original index 0, we present as 0 -> 3
// Then swap index 1 (d) and index 0 (-> 3, b)
// 1 (index) -> 0 (new index) -> 3 (real_index)
// ['d.comments', 'b.comments', 'c.comments', 'd.comments']
// index 1 is finalized
// index 3 is contains the item of original index 1
// - we present as 1 -> 3
// - it is ok that we don't remove mapping 0 -> 3
// Then index 2 should be skipped
// Then swap index 3 (d) and index 1 (-> 3, b), skipped
const map = Object.create(null)
result.forEach((source_index, index) => {
if (source_index === index) {
return
}
const real_source_index = get_mapped(map, source_index)
if (real_source_index === index) {
return
}
// The item of index `index` gets the final value
// delete map[index]
map[index] = real_source_index
swap_comments(this, index, real_source_index)
})
return this
}
}
module.exports = {
CommentArray
}