把很多复杂组件通过一个简单易使用的接口暴露出来

    1. class Buffer extends Array {
    2.   constructor(width=30, height=20){
    3.     super();
    4.     this.width = width;
    5.     this.height = height;
    6.     this.alloc(width*height)
    7.   }
    9.   write(text, position=0){
    11.   }
    12. }
    14. class Viewport {
    15.   constructor(buffer=new Buffer()){
    16.     this.buffer = buffer;
    17.     this.offset = 0;
    18.   }
    20.   append(text, pos){
    21.     this.buffer.write(text, pos + this.offset);
    22.   }
    24.   getCharAt(index){
    25.     return this.buffer[this.offset + index];
    26.   }
    27. }
    1. class Console{
    2.   constructor(){
    3.     this.buffer = new Buffer();
    4.     this.currentViewport = new Viewprot(this.buffer);
    5.     this.buffer = [this.buffer];
    6.     this.viewports = [this.currentViewport];
    7.   }
    9.   write(text){
    10.     this.currentViewport.buffer.write(text);
    11.   }
    13.   getCharAt(index){
    14.     return this.currentViewport.getChartAt(index);
    15.   }  
    16. }
    18. let c = new Console();
    19. c.write('hello');
    20. let ch = c.getCharAt(0);