js里数组名的直接赋值

const numbers = [...this.state.numbers];
    numbers.push(numbers[numbers.length-1] + 1);
    console.log(numbers === this.state.numbers);

这样子输出的是false

    const numbers = this.state.numbers;
   numbers.push(numbers[numbers.length-1] + 1);
    console.log(numbers === this.state.numbers);

但是这样输出则是true了

为什么呢？

原因很简单，这种赋值只是直接把this.state.numbers的数组指针直接给了numbers，使得numbers可以直接操作数组里面的数据

const numbers = this.state.numbers;
    //const numbers = [...this.state.numbers];
    numbers.push(numbers[numbers.length-1] + 1);
    console.log('state' + this.state.numbers);
    console.log('numbers' + numbers);

这样子输出两个数组里的内容是完全一样的，所以就造成了上面的结果了