JSON.stringify-tips.md

https://javascript.info/json

What to be converted

Acceptable value

• Objects {...}
• Arrays [...]
• Primitives:
  • strings,
  • numbers,
  • boolean values true/false
  • null

The following value will be ignored:

• Function properties(methods)
• Symbolic properties
• Properties that store undefined

For instance

let user = {
  sayHi() { // ignored
    alert("Hello");
  },
  [Symbol("id")]: 123, // ignored
  something: undefined // ignored
};

alert( JSON.stringify(user) ); // {} (empty object)

ATTENTION circular references will cause an error.

Additional parameters

The full syntax of JSON.stringify is:

const json = JSON.stringify(value[, replacer, space])

Parameter	meaning
value	A value to encode
replacer	Array of properties to encode or a mapping function function(key, value).
space	Amount of space to use for formating