我正在尝试开发一个javascript库，使我更容易生成DOM元素并编辑其属性。我遇到的问题是，某些元素有很多属性，它们会使代码变得混乱。例如，我必须在生成之前使用方法调用以编程方式设置边框，背景，阴影等的颜色。
请参阅嵌套在jLibrary.php中的函数Div中的setBorder
function Div() {
Div.POSITION = {
STATIC : 'static',
ABSOLUTE : 'absolute',
RELATIVE : 'relative',
FIXED : 'fixed'
}
Div.BORDER = {
SOLID : 'solid',
DOTTED : 'dotted'
}
Div.ALIGN = {
LEFT : 0,
CENTER : 1,
RIGHT : 2,
TOP : 0,
MIDDLE : 1,
BOTTOM : 2
}
var ELEMENT;
var CSS;
var horizontalAlign;
var verticalAlign;
var colorQueue;
(function() {
this.div = document.createElement('div');
ELEMENT = this.div;
CSS = this.div.style;
colorQueue = 'rgb(' + new Array(0, 0, 0) + ')';
document.body.appendChild(this.div);
}());
this.setPosition = function(postype) {
if (!horizontalAlign && !verticalAlign) {
CSS.position = postype;
}
}
this.setBounds = function(x, y, width, height) {
CSS.left = x + 'px';
CSS.top = y + 'px';
CSS.width = width + 'px';
CSS.height = height + 'px';
}
this.setColorQueue = function(r, g, b) {
colorQueue = 'rgb(' + new Array(r, g, b) + ')';
alert(colorQueue);
}
this.setBackgroundColorToQueue = function(){
CSS.backgroundColor = colorQueue;
}
this.createShadow = function(x, y, width, height){
CSS.boxShadow = y + 'px ' + x + 'px ' + width + 'px ' + height + 'px ' + colorQueue;
}
this.createBorder = function(width,style){
CSS.border = width + 'px ' + style + ' ' + colorQueue;
/* Theoretical Method.
this.setColor = function(r,g,b){ //This will not work the way I want it...
CSS.border = 'rgb(' + new Array(r, g, b) + ')';
}
*/
}
this.rotateDiv = function(degrees){
CSS.transform = 'rotate(' + degrees + 'deg)';
}
this.horizontalAlign = function(horiz) {
var freeSpaceX = ((window.innerWidth - ELEMENT.offsetWidth) / 2);
var defPadding = '8px';
var defPaddingCenter;
var defPaddingRight;
var defPaddingLeft;
horizontalAlign = true;
if (CSS.position == 'relative' || CSS.position == 'static' || CSS.position == 'absolute') {
CSS.position = 'absolute';
defPaddingCenter = 4;
defPaddingRight = 4;
defPaddingLeft = 8;
} else if (CSS.position == 'fixed') {
defPaddingCenter = 4;
defPaddingRight = 4;
defPaddingLeft = 8;
}
if (horiz == 0) {
if (!verticalAlign) {
CSS.marginTop = defPadding;
}
CSS.marginLeft = defPaddingLeft + 'px';
} else if (horiz == 1) {
if (!verticalAlign) {
CSS.marginTop = defPadding;
}
CSS.marginLeft = freeSpaceX - defPaddingCenter + 'px';
} else if (horiz == 2) {
if (!verticalAlign) {
CSS.marginTop = defPadding;
}
CSS.marginLeft = (freeSpaceX - defPaddingRight) * 2 + 'px';
}
}
this.verticalAlign = function(vertical) {
var freeSpaceY = ((window.innerHeight - ELEMENT.offsetHeight) / 2);
var defPadding = '8px';
var defPaddingTop;
var defPaddingMid;
var defPaddingBot;
verticalAlign = true;
if (CSS.position == 'relative' || CSS.position == 'static') {
CSS.position = 'absolute';
}
defPaddingTop = 8;
defPaddingMid = 8;
defPaddingBot = 8;
if (vertical == 0) {
if (!horizontalAlign) {
CSS.marginLeft = defPadding;
}
CSS.marginTop = defPadding;
} else if (vertical == 1) {
if (!horizontalAlign) {
CSS.marginLeft = defPadding;
}
CSS.marginTop = freeSpaceY - defPaddingMid + 'px';
} else if (vertical == 2) {
if (!horizontalAlign) {
CSS.marginLeft = defPadding;
}
CSS.marginTop = (freeSpaceY * 2) - defPaddingBot + 'px';
}
}
}
set.php中的setBorder示例
var div1 = new Div();
div1.setPosition(Div.POSITION.ABSOLUTE);
div1.setBounds(0,700, 200,200);
div1.setColorQueue(0,0,0); //This method must be called every time a different color is needed for a certain attribute.
div1.createBorder(5, Div.BORDER.SOLID); // I really want something like this --> div1.createBorder(5,Div.BORDER.SOLID).setColor(0,0,0);
答案 0 :(得分：2)
您可以尝试使用Builder pattern：
function DivBuilder() {
var color;
var border;
var position;
var bounds;
this.DivBuilder = function() {}
this.color = function(c) {
//set the color
this.color = c;
return this;
}
this.border = function(b) {
//set the border
this.border = b;
return this;
}
this.position = function(p) {
//set position
this.position = p;
return this;
}
this.bounds = function(b) {
//set bounds
this.border = b;
return this;
}
this.build = function () {
//build the new Div object with the properties of the builder
var d = new Div(this);
return d;
}
}
然后：
var divb = new DivBuilder();
divb.position().bounds().border().color();
var div = divb.buid();
telescopic constructor pattern的主要优势（以及它对javascript的适应性）是你可以更容易地选择你想要初始化的属性，而不必创建许多不同的构造函数。
答案 1 :(得分：1)
如果你想写这个.createBorder（...）。setColor（...）这意味着createBorder应该返回一个带有setColor方法的对象......
答案 2 :(得分：1)
感谢塞巴斯，我能够想出这个......如果这对你有所帮助，请投票给塞巴斯。
嵌套在this.createBorder（）
中this.createBorder = function(width) {
CSS.border = width + 'px';
function DivBorderBuilder() {
this.setColor = function(r, b, g) {
alert('color');
CSS.borderColor = 'rgb(' + new Array(r, g, b) + ')';
return this;
}
this.setStyle = function(s){
CSS.borderStyle = s;
return this;
}
}return new DivBorderBuilder();
}
在index.php中创建边框
<script>
var div1 = new Div();
div1.setPosition(Div.POSITION.ABSOLUTE);
div1.setBounds(0,700, 200,200);
div1.createBorder(5).setStyle(Div.BORDER.SOLID).setColor(255,0,0);// Works Perfectly Now !
</script>