javascript - 含义 var lineColor = { red : 'blue' , blue: 'red' }[lineColor];

Question

 $('#toggle-linecolor').click(function () {
        chart.yAxis[0].update({
            lineColor: lineColor
        });
        lineColor = { red: 'blue', blue: 'red' }[lineColor];
    });

Answer 1

它在'red'和'blue'之间切换。

假设您开始于:

var lineColor = 'red';

执行此操作会将lineColor更改为“蓝色”

lineColor = { red: 'blue', blue: 'red' }[lineColor];
// The property [red] of that object has a value of 'blue'

lineColor // <--- 'blue'

再次执行它，会将值切换为“红色”

lineColor = { red: 'blue', blue: 'red' }[lineColor];
// The property [blue] of that object has a value of 'red'

lineColor // <---- 'red'