组合模式

  • 定义：将对象组合成树形结构以表示‘部分-整体’的层次结构。
    组合模式
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// 定义组件
abstract class IComponent {
    name:string
    constructor(name:string) {
        this.name = name
    }
    add(c: IComponent) {}
    remove(c: IComponent) {}
    display(depth: number) {}
}
// 定义叶节点
class Leaf extends IComponent {
    add() {
        console.log('cannot add a leaf')
    }
    remove() {
        console.log('cannot remove from a leaf')
    }
    display(d:number) {
        console.log('-'.repeat(d)+this.name)
    }
} 
// 定义容器
class Composite extends IComponent {
    children:IComponent[] = []
    add(c: IComponent) {
        this.children.push(c)
    }
    remove(c: IComponent) {
        let i = this.children.indexOf(c)
        this.children.splice(i, 1)
    }
    display(d:number) {
        console.log('-'.repeat(d)+this.name)
        this.children.forEach(c => c.display(d + 2))
    }
}

// 使用
const root = new Composite('root')
root.add(new Leaf('leafA'))
root.add(new Leaf('leafB'))

const comp = new Composite('compX')
comp.add(new Leaf('leafXa'))

root.add(comp)

const comp2 = new Composite('compXY')

comp2.add(new Leaf('leafXYA'))

comp.add(comp2)

root.add(new Leaf('leafC'))

root.display(1)