调用更改函数之前更改了Javascript数组

Question

var state是二维数组

var state = [
    ['-', '-', '-'],
    ['-', '-', '-'],
    ['-', '-', '-']
];

console.log (state)
state [0][1] = 'G'

问题是console.log(state)在应用更改（打印为'G'后）正在向控制台打印state

var state = [
        ['-','-','-'],
        ['-','-','-'],
        ['-','-','-']
    ];

  
console.log (state);

state [0][1] = 'G';