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keksAccountGUI/node_modulesOLD/hoopy/index.js
2019-08-11 20:48:02 +02:00

103 lines
1.9 KiB
JavaScript

'use strict'
class Hoopy extends Array {
constructor (size) {
let index, isIndexOverflowed
if (! isPositiveInteger(size)) {
throw new TypeError('Argument `size` must be a positive integer.')
}
super(size)
this.grow = by => {
if (! isPositiveInteger(by)) {
throw new TypeError('Argument `by` must be a positive integer.')
}
let i
const newSize = size + by
for (i = size; i < newSize; ++i) {
this[i] = undefined
}
if (isIndexOverflowed) {
for (i = 0; i <= index; ++i) {
let j = size + i
if (j >= newSize) {
j %= newSize
}
this[j] = this[i]
this[i] = undefined
}
}
size = newSize
}
return new Proxy(this, {
get (target, key) {
if (isInteger(key)) {
return target[getIndex(key, size)]
}
return target[key]
},
set (target, key, value) {
if (isInteger(key)) {
index = getIndex(key, size)
target[index] = value
if (Math.abs(key) >= size) {
isIndexOverflowed = true
} else {
isIndexOverflowed = false
}
} else {
target[key] = value
}
return true
}
})
}
}
function isPositiveInteger (thing) {
return isInteger(thing) && thing > 0
}
function isInteger (thing) {
try {
return +thing % 1 === 0
} catch (error) {
// Coercing symbols to numbers throws an error
}
return false
}
function getIndex (key, size) {
if (key === 0) {
return 0
}
if (key < 0) {
return (size - Math.abs(key)) % size
}
return key % size
}
function nop () {
throw new Error('Not implemented')
}
Hoopy.prototype.push = nop
Hoopy.prototype.pop = nop
Hoopy.prototype.shift = nop
Hoopy.prototype.unshift = nop
module.exports = Hoopy