优化过多if else判断代码

有些判断难免会遇到很多 if else  看起来很头疼  下面是一个优化示例

修改前 

 if(this.$route.query.deptId){
            this.queryParams.deptId = this.$route.query.deptId
        }else if (this.$store.state.adaptation.roleSign.includes('fengongsicengji')) {
            const ancestorsId = this.$store.getters.dept.ancestors.split(',')
            if (ancestorsId.length === 3 || ancestorsId.length === 4) {
                this.queryParams.deptId = ancestorsId[2]
            } else if (ancestorsId.length === 2) {
                this.queryParams.deptId = ancestorsId[1]
            } else {
                this.queryParams.deptId = ancestorsId[2]
            }
        } 

修改后 

this.queryParams.deptId = this.$route.query.deptId || (this.$store.state.adaptation.roleSign.includes('fengongsicengji') ? (this.$store.getters.dept.ancestors.split(',').length === 3 ? ancestorsId[2] : ancestorsId[1]) : ancestorsId[2]);

日常中我们会忽略|| 的另一个用法 

if(1||2)  这是 1或者2   通过判断

const b =？(未知值)

const a = b|| 0    当b为不为false  a = b  如果为false  a = 0

优雅 太优雅了 优化完整个人还是虎躯一震的