Vue js with语句原理及用法解析

export function generate (
 ast: ASTElement | void,
 options: CompilerOptions
): CodegenResult {
 const state = new CodegenState(options)
 const code = ast ? genElement(ast, state) : '_c("div")'
 return {
  render: `with(this){return $[code]}`,
  staticRenderFns: state.staticRenderFns
 }
}

let obj = {
  a:"aa",
  b:"bb",
  c:""
}

// 一
let a = obj.a
//二
let b = ojb["b"]

with(obj){
  var a = a;
  var b = b;
  var c = c;
}

var qs1 = location.search.substring(1);
var hostname1 = location.hostname;
var url1 = location.href;
 
// 上面几行代码都包含了location对象，可使用with语句简写为以下形式
 
with(location){
  var qs2 = search.substring(1);
  var hostname2 = hostname;
  var url2 = href;
}