js里數組名的直接賦值

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

這樣子輸出的是false

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

但是這樣輸出則是true了

為什么呢？

原因很簡單，這種賦值只是直接把this.state.numbers的數組指針直接給了numbers，使得numbers可以直接操作數組里面的數據

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);

這樣子輸出兩個數組里的內容是完全一樣的，所以就造成了上面的結果了