Published Oct 12, 2019
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Cleaner data-structure for common algorithms based on sets.
let s = new Set()
s.add("hello").add("goodbye").add("hello")
s.size === 2
s.has("hello") === true
for (let key of s.values()) // insertion order
console.log(key)
Cleaner data-structure for common algorithms based on maps.
let m = new Map()
let s = Symbol()
m.set("hello", 42)
m.set(s, 34)
m.get(s) === 34
m.size === 2
for (let [ key, val ] of m.entries())
Memory-leak-free Object-key’d side-by-side data-structure.
let isMarked = new WeakSet()
let attachedData = new WeakMap()
export class Node {
constructor (id) { this.id = id }
mark () { isMarked.add(this) }
unmark () { isMarked.delete(this) }
marked () { return isMarked.has(this) }
set data (data) { attachedData.set(this, data) }
get data () { return attachedData.get(this) }
}
let foo = new Node("foo")
JSON.stringify(foo) === '{"id":"foo"}'
foo.mark()
foo.data = "bar"
foo.data === "bar"
JSON.stringify(foo) === '{"id":"foo"}'
isMarked.has(foo) === true
attachedData.has(foo) === true
foo = null /* remove only reference to foo */
attachedData.has(foo) === false
isMarked.has(foo) === false
Support for arbitrary byte-based data structures to implement network protocols, cryptography algorithms, file format manipulations, etcc.
// ES6 class equivalent to the following C structure:
// struct Example { unsigned long id; char username[16]; float amountDue }
class Example {
constructor (buffer = new ArrayBuffer(24)) {
this.buffer = buffer
}
set buffer (buffer) {
this._buffer = buffer
this._id = new Uint32Array (this._buffer, 0, 1)
this._username = new Uint8Array (this._buffer, 4, 16)
this._amountDue = new Float32Array(this._buffer, 20, 1)
}
get buffer () { return this._buffer }
set id (v) { this._id[0] = v }
get id () { return this._id[0] }
set username (v) { this._username[0] = v }
get username () { return this._username[0] }
set amountDue (v) { this._amountDue[0] = v }
get amountDue () { return this._amountDue[0] }
}
let example = new Example()
example.id = 7
example.username = "John Doe"
example.amountDue = 42.0
References: