# unionWith

# Description

这个方法类似 union，除了它接受一个 comparator 调用比较 arrays 数组的每一个元素。 comparator 调用时会传入 2 个参数： (arrVal, othVal)。

# Params

(...arrays)

# Return

Array

# Depend

import baseFlatten from './.internal/baseFlatten.js'
import baseUniq from './.internal/baseUniq.js'
import isArrayLikeObject from './isArrayLikeObject.js'
import last from './last.js'

baseFlatten 源码分析

 baseUniq 源码分析

 isArrayLikeObject 源码分析

 last 源码分析

# Code

function unionWith(...arrays) {
  let comparator = last(arrays)
  comparator = typeof comparator === 'function' ? comparator : undefined
  return baseUniq(baseFlatten(arrays, 1, isArrayLikeObject, true), undefined, comparator)
}

# Analyze

整体逻辑和 unionBy 类似，只不过这里的判断比 unionBy 严谨，到最后也是传递 comparator 给 baseUniq 使用

# Example

console.log(unionWith([1,2,3],['2',3,4],['3','4',5], (x,y) => x==y)) // [ 1, 2, 3, 4, 5 ]

← unionBy uniq →