JavaScript 按位或赋值

• 就是一个字节一个字节判断

let a = 5;      // 00000000000000000000000000000101
a |= 3;         // 00000000000000000000000000000011
console.log(a); // 00000000000000000000000000000111

let a = 5;      // 00000000000000000000000000000101
a |= 4;         // 00000000000000000000000000000100
console.log(a); // 00000000000000000000000000000101