阵列串联与+和concat不同

考虑一下:

[1, 2, 3] + [4, 5, 6] // "1,2,34,5,6"
[1, 2, 3].concat([4, 5, 6]) // [1, 2, 3, 4, 5, 6]

在数组上使用plus concatenation运算符将使数组经历以下步骤:

[1, 2, 3] + [4, 5, 6]
[1, 2, 3].toString() + [4, 5, 6].toString()
"1,2,3" + "4,5,6"
"1,2,34,5,6"