ECMAScript 2023的特性

[yayxs]

/**
 * 从数组的末尾开始搜索数组
 *
 * @since 2023
 * @see
 * @example
 */

const array = [{ v: 2023 }, { v: 2022 }]

console.log(array.findLast((ele) => ele.v === 2022)) // { v: 2023 }
console.log(array.findLastIndex((ele) => ele.v > 2023)) // -1

/**
 * 非破坏性的 反转旧数组
 *
 * @since 2023
 * @see
 * @example
 *
 * //
 */

const oldArray = ['1', '2', '3']
const newArray = oldArray.toReversed()

console.log('oldArray', oldArray)
console.log('newArray', newArray)

/**
 * 非破坏性的 排序数组
 *
 * @since 2023
 * @see
 * @example
 *
 */

const oldArray1 = ['3', '2', '1']
const newArray1 = oldArray1.toSorted()

console.log('oldArray', oldArray1) // ['3', '2', '1']
console.log('newArray', newArray1) // ['1', '2', '3']

/**
 * 非破坏性的
 *
 * @since 2023
 * @see
 * @example
 *
 */

const oldArray2 = ['1', '2', '3']
const newArray2 = oldArray1.toSpliced(1, 2, 'x')
console.log(oldArray2)
console.log(newArray2)

/**
 * with
 *
 * @since 2023
 * @see
 * @example
 *
 */

const oldArray3 = ['1', '2', '3']
const newArray3 = oldArray3.with(1, 'X')

console.log(oldArray3) // ['1', '2', '3']
console.log(newArray3) // ['1', 'X', '3']

/**
 * weakmap
 *
 * @since 2023
 * @see
 * @example
 *
 */

const wm = new WeakMap()

// Symbol 的 key
const key = Symbol('sym-key')
const object = {}
wm.set(key, object)