Object.stringify 循环引用 bug & TypeError: Converting circular structure to JSON

var obj = {

  a: "foo",

};

// undefined

obj;

//{a: "foo"}

obj.b = obj;

// {a: "foo", b: {…}}

JSON.stringify(obj);

/*

VM205:1 Uncaught TypeError: Converting circular structure to JSON

    --> starting at object with constructor 'Object'

    --- property 'b' closes the circle

    at JSON.stringify (<anonymous>)

    at <anonymous>:1:6

*/