📘array methods

JS ⟩ object ⟩ built-in ⟩ Array ⟩ methods

🔴 主題

• 🔰 accessing elements

  • push() - append element.

  • pop() - remove and return last element.

  • unshift() - prepend element.

  • shift() - remove and return first element.

  • splice - delete/insert elements.

  • arr.last

  • arr.randomElement

• filter elements

  • filter - "holes" are removed automatically.

  • arr.max()

  • arr.removeDuplicates()

  • arr.removeUndefined()

  • arr.removeValue()

• combine elements

  • join - 連接所有元素、合併成一個字串。

  • reduce((result, element, index, array) => {...}) -

  • reduceRight - reduce array from highest index to lowest. (from right to left)

• find & search elements

  • find - 回傳第一個符合條件的元素。否則回傳 undefined。

  • findIndex - returns index of first matching element, -1 otherwise.

  • includes - 判斷陣列是否包含特定元素。

  • some - 測試陣列中是否有符合條件的元素。

  • every - returns true if every element satisfies the condition.

  • arr.none()

  • arr.containsSubarray()

• sort elements

  • reverse - reverse an array in place.

  • arr.reversed()

  • arr.shuffle()

• transform arrays/elements

  • map -

  • flat - flatten nested arrays to the specified level (1 if not specified)

  • flatMap - similar to arr.map(f).flat().

  • arr.uniqueMerge()

🔴 表格