提前将 template 编译成 ANode,可以避免在浏览器端进行 template 解析,提高初始装载性能。ANode 是个 JSON Object,stringify 后体积较大,需要设计一种压缩,让其体积更小,网络传输成本更低。
ANode 压缩,简称 APack
设计目标和约束有:
- 体积较小
- 解压缩过程快
基于以上,基本方案为:
- 使用一维 JS Array 作为压缩后的对象。符合 JS 能解析,解压缩过程一次遍历完成。
- 对不同类型的节点对象,包含的属性是固定的。通过
{number}head
标识类型,然后依次读取,节点对象中的属性名完全被删除。 - 空的数组、对象等值,以 undefined 忽略,数组中形态可能是
[1,,]
,进一步减少体积。 - 自己实现 stringify。JSON 中不包含 undefined 类型,使用 JSON stringify 会把 undefined 输出成 null。
- 对于 ANode 中数组类型的值,压缩后第一项为数组长度,然后依次为数组 item。
- 泛属性节点(普通属性、双向绑定属性、指令、事件、var)由
{number}head
独立标识。 - 根据 ANode 中出现的频度,以 0 和 1 标识模板节点,以 2 标识 普通属性节点,3-32 为表达式节点,33-99 为特殊泛属性节点(双向绑定属性、指令、事件、var)。
- bool true 以 1 表示,bool false 以 undefined 表示,compressed 为空
- head: 0
- 编码序:
{Node}textExpr
aPack = [,9,,2,3,"Hello ",7,,6,1,3,"name",]
/*
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 1,
"value": "Hello "
},
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
]
}
}
*/
- head: 1
- 编码序:
{string?}tagName, {Array<Node>}propsAndChildren, {Array<Node>?}elses
aPack = [1,"dd",3,38,6,1,3,"list",37,"item",,,6,1,3,"list",,9,,1,7,,6,1,3,"item",,]
/*
{
"directives": {
"if": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "list"
}
]
}
},
"for": {
"item": "item",
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "list"
}
]
}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "item"
}
]
},
"filters": []
}
]
}
}
],
"tagName": "dd"
}
*/
- head: 3
- 编码序:
{string}value
aPack = [3,"Hello"]
/*
{
"type": 1,
"value": "Hello"
}
*/
- head: 4
- 编码序:
{number}value
aPack = [4,10]
/*
{
"type": 2,
"value": 10
}
*/
- head: 5
- 编码序:
{bool}value
aPack = [5,1]
/*
{
"type": 3,
"value": true
}
*/
- head: 6
- 编码序:
{Array}paths
aPack = [6,1,3,"name"]
/*
{
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
}
*/
- head: 7
- 编码序:
{bool}original, {Node}expr, {Array<Node>}filters
aPack = [7,,6,1,3,"name",]
/*
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
*/
- head: 8
- 编码序:
{Node}name, {Array<Node>}args
aPack = [8,6,1,3,"showToast",1,6,1,3,"msg"]
/*
{
"type": 6,
"name": {
"type": 4,
"paths": [
{
"type": 1,
"value": "showToast"
}
]
},
"args": [
{
"type": 4,
"paths": [
{
"type": 1,
"value": "msg"
}
]
}
]
}
*/
- head: 9
- 编码序:
{bool}original, {Array<Node>}segs
aPack = [9,,2,3,"Hello ",7,,6,1,3,"name",]
/*
{
"type": 7,
"segs": [
{
"type": 1,
"value": "Hello "
},
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
]
}
*/
- head: 10
- 编码序:
{number}operator, {Node}first, {Node}second
aPack = [10,43,6,1,3,"num",4,1]
/*
{
"type": 8,
"operator": 43,
"segs": [
{
"type": 4,
"paths": [
{
"type": 1,
"value": "num"
}
]
},
{
"type": 2,
"value": 1
}
]
}
*/
- head: 11
- 编码序:
{number}operator, {Node}expr
aPack = [11,33,6,1,3,"exists"]
/*
{
"type": 9,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "exists"
}
]
},
"operator": 33
}
*/
- head: 12
- 编码序:
{Node}condExpr, {Node}truthyExpr, {Node}falsyExpr
aPack = [12,6,1,3,"exists",6,1,3,"num",4,0]
/*
{
"type": 10,
"segs": [
{
"type": 4,
"paths": [
{
"type": 1,
"value": "exists"
}
]
},
{
"type": 4,
"paths": [
{
"type": 1,
"value": "num"
}
]
},
{
"type": 2,
"value": 0
}
]
}
*/
- head: 13
- 编码序:
{Array<Node>}items
aPack = [13,2,14,3,"key",6,1,3,"key",15,6,1,3,"ext"]
/*
{
"type": 11,
"items": [
{
"name": {
"type": 1,
"value": "key"
},
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "key"
}
]
}
},
{
"spread": true,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "ext"
}
]
}
}
]
}
*/
- head: 14
- 编码序:
{Node}name, {Node}expr
aPack = [14,3,"key",6,1,3,"key"]
/*
{
"name": {
"type": 1,
"value": "key"
},
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "key"
}
]
}
}
*/
- head: 15
- 编码序:
{Node}expr
aPack = [15,6,1,3,"ext"]
/*
{
"spread": true,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "ext"
}
]
}
}
*/
- head: 16
- 编码序:
{Array<Node>}items
aPack = [16,3,17,4,1,17,6,1,3,"two",18,6,1,3,"ext"]
/*
{
"type": 12,
"items": [
{
"expr": {
"type": 2,
"value": 1
}
},
{
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "two"
}
]
}
},
{
"spread": true,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "ext"
}
]
}
}
]
}
*/
- head: 17
- 编码序:
{Node}expr
aPack = [17,4,1]
/*
{
"expr": {
"type": 2,
"value": 1
}
}
*/
- head: 18
- 编码序:
{Node}expr
aPack = [18,6,1,3,"ext"]
/*
{
"spread": true,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "ext"
}
]
}
}
*/
- head: 19
- 编码序: 无
aPack = [19]
/*
{
"type": 13
}
*/
- head: 2
- 编码序:
{string}name, {Node}expr
aPack = [2,"title",9,,2,3,"Hello ",7,,6,1,3,"name",]
/*
{
"name": "title",
"expr": {
"type": 7,
"segs": [
{
"type": 1,
"value": "Hello "
},
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
]
}
}
*/
- head: 33
- 编码序:
{string}name, {Node}expr
aPack = [33,"disabled",5,1]
/*
{
"name": "disabled",
"expr": {
"type": 3,
"value": true
},
"noValue": 1
}
*/
- head: 34
- 编码序:
{string}name, {Node}expr
aPack = [34,"value",6,1,3,"name"]
/*
{
"name": "value",
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"x": 1
}
*/
- head: 35
- 编码序:
{string}name, {Node}expr, {ObjectAsArray}modifier
aPack = [35,"click",8,6,1,3,"showToast",1,6,1,3,"msg",]
/*
{
"name": "click",
"modifier": {},
"expr": {
"type": 6,
"name": {
"type": 4,
"paths": [
{
"type": 1,
"value": "showToast"
}
]
},
"args": [
{
"type": 4,
"paths": [
{
"type": 1,
"value": "msg"
}
]
}
]
}
}
*/
- head: 36
- 编码序:
{string}name, {Node}expr
aPack = [1,"dd",1,36,"name",6,2,3,"user",3,"name"]
/*
{
"directives": {},
"props": [],
"events": [],
"children": [],
"tagName": "dd",
"vars": [
{
"name": "name",
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "user"
},
{
"type": 1,
"value": "name"
}
]
}
}
]
}
*/
- head: 37
- 编码序:
{string}item, {string?}index, {string?}trackByRaw, {Node}value
- 注: trackBy 通过 trackByRaw 二次解析
aPack = [1,"li",2,37,"item",,,6,1,3,"list",,9,,1,7,,6,1,3,"item",]
/*
{
"directives": {
"for": {
"item": "item",
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "list"
}
]
}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "item"
}
]
},
"filters": []
}
]
}
}
],
"tagName": "li"
}
*/
- head: 38
- 编码序:
{Node}value
aPack = [1,"h2",2,38,6,1,3,"title",,9,,1,7,,6,1,3,"title",,]
/*
{
"directives": {
"if": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "title"
}
]
}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "title"
}
]
},
"filters": []
}
]
}
}
],
"tagName": "h2"
}
*/
- head: 39
- 编码序:
{Node}value
aPack = [1,"h2",2,38,6,1,3,"name",,9,,1,7,,6,1,3,"name",,1,1,"b",2,39,6,1,3,"shortname",,9,,1,7,,6,1,3,"shortname",]
/*
{
"directives": {
"if": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
]
}
}
],
"tagName": "h2",
"elses": [
{
"directives": {
"elif": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "shortname"
}
]
}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "shortname"
}
]
},
"filters": []
}
]
}
}
],
"tagName": "b"
}
]
}
*/
- head: 40
- 编码序: 无
- 注: 为保持一致,自生成
{value:{}}
aPack = [1,"h2",2,38,6,1,3,"name",,9,,1,7,,6,1,3,"name",,1,1,"span",2,40,,3,"noname"]
/*
{
"directives": {
"if": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 7,
"segs": [
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
]
}
}
],
"tagName": "h2",
"elses": [
{
"directives": {
"else": {
"value": {}
}
},
"props": [],
"events": [],
"children": [
{
"textExpr": {
"type": 1,
"value": "noname"
}
}
],
"tagName": "span"
}
]
}
*/
- head: 41
- 编码序:
{Node}value
aPack = [1,"x-item",1,41,9,,2,3,"item",7,,6,1,3,"i",]
/*
{
"directives": {
"ref": {
"value": {
"type": 7,
"segs": [
{
"type": 1,
"value": "item"
},
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "i"
}
]
},
"filters": []
}
]
}
}
},
"props": [],
"events": [],
"children": [],
"tagName": "x-item"
}
*/
- head: 42
- 编码序:
{Node}value
aPack = [1,"x-info",1,42,6,1,3,"user"]
/*
{
"directives": {
"bind": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "user"
}
]
}
}
},
"props": [],
"events": [],
"children": [],
"tagName": "x-info"
}
*/
- head: 43
- 编码序:
{Node}value
aPack = [1,"u",1,43,6,1,3,"text"]
/*
{
"directives": {
"html": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "text"
}
]
}
}
},
"props": [],
"events": [],
"children": [],
"tagName": "u"
}
*/
- head: 44
- 编码序:
{Node}value
aPack = [1,"x-item",1,44,8,6,1,3,"trans",]
/*
{
"directives": {
"transition": {
"value": {
"type": 6,
"name": {
"type": 4,
"paths": [
{
"type": 1,
"value": "trans"
}
]
},
"args": []
}
}
},
"props": [],
"events": [],
"children": [],
"tagName": "x-item"
}
*/
- head: 45
- 编码序:
{Node}value
aPack = [1,"u",1,45,6,1,3,"cmpt"]
/*
{
"directives": {
"is": {
"value": {
"type": 4,
"paths": [
{
"type": 1,
"value": "cmpt"
}
]
}
}
},
"props": [],
"events": [],
"children": [],
"tagName": "u"
}
*/
- head: 46
- 编码序:
{string}name, {Node}expr
aPack = [1,"my-ui",1,46,"title",9,,2,3,"Hello ",7,,6,1,3,"name",]
/*
{
"directives": {},
"props": [],
"events": [],
"children": [],
"tagName": "my-ui",
"attrs": [
{
"name": "title",
"expr": {
"type": 7,
"segs": [
{
"type": 1,
"value": "Hello "
},
{
"type": 5,
"expr": {
"type": 4,
"paths": [
{
"type": 1,
"value": "name"
}
]
},
"filters": []
}
]
}
}
]
}
*/