products = [{"name":"Pizza","price":"10","quantity":"7"}, {"name":"Cerveja","price":"12","quantity":"5"}, {"name":"Hamburguer","price":"10","quantity":"2"}, {"name":"Fraldas","price":"6","quantity":"2"}];

改变

products = '[{"name":"Pizza","price":"10","quantity":"7"}, {"name":"Cerveja","price":"12","quantity":"5"}, {"name":"Hamburguer","price":"10","quantity":"2"}, {"name":"Fraldas","price":"6","quantity":"2"}]';

[
  {
    "name": "Pizza",
    "price": "10",
    "quantity": "7"
  },
  {
    "name": "Cerveja",
    "price": "12",
    "quantity": "5"
  },
  {
    "name": "Hamburguer",
    "price": "10",
    "quantity": "2"
  },
  {
    "name": "Fraldas",
    "price": "6",
    "quantity": "2"
  }
]

下面是您可以解析的完美JSON内容。

products = [{"name":"Pizza","price":"10","quantity":"7"}, {"name":"Cerveja","price":"12","quantity":"5"}, {"name":"Hamburguer","price":"10","quantity":"2"}, {"name":"Fraldas","price":"6","quantity":"2"}];

改变

products = '[{"name":"Pizza","price":"10","quantity":"7"}, {"name":"Cerveja","price":"12","quantity":"5"}, {"name":"Hamburguer","price":"10","quantity":"2"}, {"name":"Fraldas","price":"6","quantity":"2"}]';

唯一的错误是您正在解析一个已经解析过的对象，因此它抛出一个错误。用这个你就可以走了。

Var product = [{ “名称”:“披萨”, “价格”:“10”, “数量”:“7” },{ “名称”:“Cerveja”, “价格”:“12”, “数量”:“5” },{ “名称”:“汉堡”, “价格”:“10”, “数量”:“2” },{ “名称”:“Fraldas”, “价格”:“6”, “数量”:“2” }); console.log(产品[0]. name);//第0个索引项的名称

如果想打印整个JSON内容，请使用JSON.stringify()。

Products是一个对象。(从对象字面量创建)

JSON.parse()用于将包含JSON符号的字符串转换为Javascript对象。

您的代码将对象转换为字符串(通过调用. tostring())，以便尝试将其解析为JSON文本。 默认的.toString()返回"[object object]"，这不是有效的JSON;因此出现了错误。

如果有前导空格或尾随空格，则无效。 后面和前面的空格可以被删除为

mystring = mystring.replace(/^\s+|\s+$/g, "");

删除字符串的前导或尾随空格