语法

JSON.stringify(value[, replacer [, space]])

replacer为函数

function replacer(key, value) {
  if (typeof value === "string") {
    return undefined;
  }
  return value;
}

var foo = {foundation: "Mozilla", model: "box", week: 45, transport: "car", month: 7};
var jsonString = JSON.stringify(foo, replacer); // "{"week":45,"month":7}"

replacer为数组，只保留存在于数组中的key

var foo = {foundation: "Mozilla", model: "box", week: 45, transport: "car", month: 7};
var jsonString = JSON.stringify(foo, ['week', 'month']); // "{"week":45,"month":7}"

space

JSON.stringify({ uno: 1, dos : 2 }, null, '\t')
// '{            \
//     "uno": 1, \
//     "dos": 2  \
// }'

其他MDN中介绍的很详细