合并两个数组报错,为何呢?

Question

let arrA = [1,2,3]
let arrB = [3,4,5,6]
let result = []
// 这里合并数组 报 Unexpected token
[...arrA,...arrB].forEach(item => {
  if(arrA.includes(item)&&!arrB.includes(item)) result.push(item)
})
console.log(result)

这样就没问提:

Array.from([...arrA,...arrB]).forEach(item => {
  if(arrA.includes(item)&&!arrB.includes(item)) result.push(item)
})

Answer 1

这是 JS自动加分号的规则导致的,相关问题:
What are the rules for JavaScript's automatic semicolon insertion (ASI)?

Answer 2

let arrA = [1,2,3]
let arrB = [3,4,5,6]
let result = []; // 这里加个分号

[...arrA,...arrB].forEach(item => {
  if(arrA.includes(item)&&!arrB.includes(item)) result.push(item)
})
console.log(result)

具体原因,解释器的问题 有点小复杂 总之加分号没毛病