如何告诉push以避免附加重复值？

b.push(a);如果b为空(b = [])或者值如下,如何避免添加重复项？

var a = ["username1", "1"];
var b = [ ["username1", "1"], ["username2", "2"] ];
b.push(a);

Nenad Vracar.. 5

您可以使用some()并every()首先检查是否a存在b,然后使用push.

var a = ["username1", "1"];
var b = [ ["username1", "1"], ["username2", "2"] ];

var check = b.some(function(e) {
  return a.length == e.length && a.every(function(c) {
    return e.includes(c)
  })
})

if (!check) b.push(a);
console.log(b)

var a = ["username1", "1"];
var b = [ ["username1", "1"], ["username2", "2"] ];

var check = b.some(function(e) {
  return a.length == e.length && a.every(function(c) {
    return e.includes(c)
  })
})

if (!check) b.push(a);
console.log(b)