with在模板中的应用

var str = ‘Hello <%= name %>!‘;

var o = {
  name: ‘Alice‘
};

function tmpl(str, obj) {
  str = ‘var p = [];‘ +
    ‘with (obj) {p.push(‘ + parser(str) + ‘)};‘ +
    ‘return p;‘
  var r = (new Function(‘obj‘, str))(obj);
  return r.join(‘‘);
}

tmpl(str, o)

推测parser应该是返回"hello" ,"Alice","!"

代码就变成：

var str = ‘Hello <%= name %>!‘;

var o = {
name: ‘Alice‘
};

function tmpl(str, obj) {
str = ‘var p = [];‘ +
　　‘with (obj) {p.push("hello" ,"Alice","!")};‘ +
　　‘return p;‘
　　var r = (new Function(‘obj‘, str))(obj);
　　return r.join(‘‘);
}

tmpl(str, o)

核心部分就是：

var o = {
  name: ‘Alice‘
};

var p = [];

with (o) {
  p.push(‘Hello ‘, name, ‘!‘);
};

p.join(‘‘)