String-ES6

string.codePointAt()能处理4个字节

string.charCodeAt()处理2个字节

// 是否由四个字节组成
function is32Bit(c){
	return c.codePointAt(0) > 0xFFFF;
}

string.fromCharCode(0xFFFF)
string.fromCodePoint(0x20BB7)
如果String.fromCharCode方法有多个参数，则它们会被合并成一个字符串返回。String.fromCodePoint(0x78, 0x1f680, 0x79) === “x\uD83D\uDE80y” // true
fromCodePoint 方法定义在String对象上，codePointAt方法定义在字符串实例对象上
for(let xx of string) 可以识别大于0xFFFF的码点
string.at()和string.charAt()
string.includes()
string.endsWith(sting1,index)
string.startsWith()
string.padStart(length,string1) //length是拼接string1后总长度，超出部分截出
string.padEnd(length,string1)
templete
``反引号成行成段转义输出
let man = 6
$(‘#J_main’).append(<b>${man}</b>) // 6
${内部执行的是JavaScript代码}
${‘hello’ + ‘ world’}
console.log(${man}+${man});
console.log(${man + man});
let xx = (x)=>{return x;}
console.log(${xx(21)})
let lo = (function fk(x){ return x}) // 要用括号把函数体包裹起来
let fuc = eval(lo)
console.log(fuc(223))
string.raw //转义\

简单模板

var template = `
<ul>
  <% for(var i=0; i < data.supplies.length; i++) {%>
    <li><%= data.supplies[i] %></li>
  <% } %>
</ul>
`;
function compile(template){
  var evalExpr = /<%=(.+?)%>/g;
  var expr = /<%([\s\S]+?)%>/g;

  template = template
    .replace(evalExpr, '`); \n  echo( $1 ); \n  echo(`')
    .replace(expr, '`); \n $1 \n  echo(`');

  template = 'echo(`' + template + '`);';

  // console.log(template);
  var script =
  `(function partse(data){
    var output = "";

    function echo(html){
      output += html;
    }
    ${ template }

    return output;
  })`;

  return script;
}

var parse = eval(compile(template));
console.log(parse({ supplies: [ "broom", "mop", "cleaner" ] }));

标签模板
1
tag`Hello ${main}`

templete