3 ms·

> More pragmatically, regardless of what the spec says, a ton of JSON tooling assumes the order doesn't matter and relying on it would be a big mistake. Agreed

by Garlef 6y ago

> More pragmatically, regardless of what the spec says, a ton of JSON tooling assumes the order doesn't matter and relying on it would be a big mistake. Agreed. But this does not mean that a tool should break it. My assumption would be that fn(parse(pretty_print(someJSONString))) should always evaluate to the same as fn(someJSONString) (for all functions fn)

fiddlerwoaroof 6y ago
JavaScript objects are ordered maps (as are PHP’s arrays, iirc): it’s not common, but relying on this is specified behavior in JavaScript: it would be a little surprising for JSON object literals to follow a different rule.
- dragonwriter 6y ago
  > JavaScript objects are ordered maps (as are PHP’s arrays, iirc): it’s not common, but relying on this is specified behavior in JavaScript: it would be a little surprising for JSON object literals to follow a different rule. JSON object literals expressly follow a different rule (are expliclty unordered) per the IETF specs and have no specific significance to order at the JSON level though some might conceivably be introduced in ancillary specifications or tooling per the bigECMA spec. JSON is syntactically a subset of JS but not semantically identical. Unambiguous order would require an array of one-entry objects in JSON.
  - fiddlerwoaroof 6y ago
    This isn’t true, the ECMA spec for JSON specifies that order is treated in an implementation-defined fashion. > An object structure is represented as a pair of curly bracket tokens surrounding zero or more name/value pairs. A name is a string. A single colon token follows each name, separating the name from the value. A single comma token separates a value from a following name. The JSON syntax does not impose any restrictions on the strings used as names, does not require that name strings be unique, and does not assign any significance to the ordering of name/value pairs. These are all semantic considerations that may be defined by JSON processors or in specifications defining specific uses of JSON for data interchange. https://www.ecma-international.org/wp-content/uploads/ECMA-404_2nd_edition_december_2017.pdf https://www.ecma-international.org/wp-content/uploads/ECMA-4... This wording allows a particular implementation to define its own meaning to the order of key-value pairs, or even to produce a multimap.

by Garlef 6y ago

fiddlerwoaroof 6y ago

JavaScript objects are ordered maps (as are PHP’s arrays, iirc): it’s not common, but relying on this is specified behavior in JavaScript: it would be a little surprising for JSON object literals to follow a different rule.

dragonwriter 6y ago
> JavaScript objects are ordered maps (as are PHP’s arrays, iirc): it’s not common, but relying on this is specified behavior in JavaScript: it would be a little surprising for JSON object literals to follow a different rule. JSON object literals expressly follow a different rule (are expliclty unordered) per the IETF specs and have no specific significance to order at the JSON level though some might conceivably be introduced in ancillary specifications or tooling per the bigECMA spec. JSON is syntactically a subset of JS but not semantically identical. Unambiguous order would require an array of one-entry objects in JSON.
- fiddlerwoaroof 6y ago
  This isn’t true, the ECMA spec for JSON specifies that order is treated in an implementation-defined fashion. > An object structure is represented as a pair of curly bracket tokens surrounding zero or more name/value pairs. A name is a string. A single colon token follows each name, separating the name from the value. A single comma token separates a value from a following name. The JSON syntax does not impose any restrictions on the strings used as names, does not require that name strings be unique, and does not assign any significance to the ordering of name/value pairs. These are all semantic considerations that may be defined by JSON processors or in specifications defining specific uses of JSON for data interchange. https://www.ecma-international.org/wp-content/uploads/ECMA-404_2nd_edition_december_2017.pdf https://www.ecma-international.org/wp-content/uploads/ECMA-4... This wording allows a particular implementation to define its own meaning to the order of key-value pairs, or even to produce a multimap.