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每个方法都有相应的描述、语法、参数、返回值、注意项（可选）、例子（可选）。
语法中的[]里面中的内容表示参数为可选参数。

Array.from()

描述：从一个类似数组或可迭代对象中创建一个新的数组实例。

语法：

new_array = Array.from(arrayLike[, callback(element[, index[, array]])[, thisArg]]);

8987 - Subsequence

by jiangshan (@jiangshanmeta) #中等 #union

题目

Given an array of unique elements, return all possible subsequences.

A subsequence is a sequence that can be derived from an array by deleting some or no elements without changing the order of the remaining elements.

9142 - CheckRepeatedChars

by Hong (@RThong) #中等 #union #string

题目

判断一个string类型中是否有相同的字符

type CheckRepeatedChars<'abc'>   // false
type CheckRepeatedChars<'aba'>   // true

9286 - FirstUniqueCharIndex

by jiangshan (@jiangshanmeta) #中等 #string

题目

Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1. (Inspired by leetcode 387)

5153 - IndexOf

by Pineapple (@Pineapple0919) #中等 #array

题目

Implement the type version of Array.indexOf, indexOf<T, U> takes an Array T, any U and returns the index of the first U in Array T.

5310 - Join

by Pineapple (@Pineapple0919) #中等 #array

题目

Implement the type version of Array.join, Join<T, U> takes an Array T, string or number U and returns the Array T with U stitching up.

5821 - MapTypes

by Krzysztof "Wokay" Łokaj (@wokayme) #中等 #map #object #utils

题目

Implement MapTypes<T, R> which will transform types in object T to different types defined by type R which has the following structure

type StringToNumber = {
  mapFrom: string; // value of key which value is string
  mapTo: number; // will be transformed for number
}

7544 - Construct Tuple

by Lo (@LoTwT) #中等 #tuple

题目

构造一个给定长度的元组。

例如

type result = ConstructTuple<2> // 期望得到 [unknown, unkonwn]

8640 - Number Range

by AaronGuo (@HongxuanG) #中等

题目

Sometimes we want to limit the range of numbers...
For examples.

type result = NumberRange<2 , 9> //  | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

8767 - Combination

by Homyee King (@HomyeeKing) #中等 #array #application #string

题目

Given an array of strings, do Permutation & Combination.
It's also useful for the prop types like video controlsList