5 ms·

JSON 3: A modern JSON polyfill compatible with nearly all JavaScript platforms.

41 points by kitcambridge 15y ago

jacobolus 15y ago
Thanks for the heads up. I’ve always thought JSON2’s approach of adding all kinds of stuff to built-in objects was a dumb idea for such an important piece of infrastructure code. I’ve been tempted on occasion to write my own JSON codec. I’m glad they tested to make sure it works on every browser of the last 6-7 years: it means JSON3 can pretty much be dropped in and forgotten about for any project. Unrelated: their readme reveals a bug in github’s markdown implementation. The bold is not properly applied in the following example: - **`String.prototype` Methods**: `indexOf`, `charAt`, `slice`.
- kitcambridge 15y ago
  Fixed. Thanks for the heads-up!
spicyj 15y ago
I'd be slightly worried that overriding the native functions could lead to problems in certain situations that rely on the (wrong) existing behavior.
- udp 15y ago
  I don't think it's intended as a replacement for the native functions, rather an implementation to use where they're missing (which, AFAIK, is rare nowadays).
  - spicyj 15y ago
    If you read the description on the page, it says that they fix certain broken aspects of some native implementations.
    - jdd 15y ago
      @spicyj I agree that recklessly paving natives is no good and can cause problems, but JSON3 is trying rather hard to not pave them (note that it doesn't even extend Date.prototype), and only paves parse/stringify when fixing broken implementations that are not cross-browser consistent or spec-compliant. With the fix in place it means the API will produce consistent output cross-browser which is a good thing.
    - kitcambridge 15y ago
      That's correct. Currently, Firefox is the only browser that implements the JSON routines exactly as described in the spec (parsing since version 5.0, and serializing since 6.0)...others deviate in one or more ways. It's not so much of a concern if you're targeting multiple browsers, as Firefox will correctly throw a `SyntaxError` when given malformed input, but it can certainly become problematic if you're relying on non-standard extensions in only one or two browsers.
deleted 15y ago
[deleted]
arturadib 15y ago
Speaking of new JSON versions, is it impossible to create a backwards-compatible JSON spec that supports comments? I've been waiting for this for ages.
- jsdalton 15y ago
  Please, yes. Two use cases where I constantly bemoan the lack of comment support in JSON are configuration files and test fixtures.
- kitcambridge 15y ago
  I, too, would love to see comments officially supported in the next iteration of the JSON standard...IIRC, Crockford removed them to make JSON a valid YAML subset. For what it's worth, I've created a fork of Kyle Simpson's `JSON.minify` project that uses a variation of the character-based parsing process in JSON 3: https://github.com/kitcambridge/JSON.minify/blob/master/minify-sans-regexp.js https://github.com/kitcambridge/JSON.minify/blob/master/mini... It's somewhat cumbersome to use, though, as it needs to be called on a string before feeding it to `parse` (e.g., `JSON.parse(JSON.minify("/* Hello */ 123"))`).
- kodablah 15y ago
  Optional quotes and optional EOL commas would be nice too
  - akavlie 15y ago
    While more human friendly, that would inhibit serialization.
- wvenable 15y ago
  Comments were removed for several reasons; one being that it adds the ability to add non-JSON data to the stream. In order to keep the spec simple and more interoperable, comments are gone. Don't expect them to return.
steele 15y ago
unicode support? damn you u+2028
prodigal_erik 15y ago
If anyone else was confused, a "polyfill" is a pure javascript implementation of behavior the platform doesn't natively provide, and calling it "JSON 3" is not trying to claim that the JSON grammar has been revised (that's pretty much impossible); it's just the unfortunately generic name they chose for this implementation.
- benatkin 15y ago
  I understood the JSON3 name right away. Douglas Crockford's best-known implementation is called JSON2; this aims to be a successor to it. I agree that it shouldn't be called a polyfill.
- jdd 15y ago
  @prodigal_erik @benatkin It is a JS polyfill/shim/fallback for older browsers like IE 6 and 7 but also fixes/fills in gaps in support/consistency with modern browsers that have buggy implementations. The use of the word "modern" in the description is to suggest it is more up-to-date than Crockford's aging/stale json2.js.
polemic 15y ago
This is bike-shed, but `stringify`? What's wrong with `serialize` or `toJSON` or `toString'?
- shantanubala 15y ago
  This is mainly for consistency with the previous JSON libraries developed by Douglas Crockford. In JavaScript, it's easy enough to "create your own API" by just aliasing JSON.stringify to JSON.serialize or even a local "serialize" function that it isn't too much of an issue. As much as I agree that the naming convention isn't great, it's better to have consistency -- especially in a language as dynamic as JavaScript.
- jdd 15y ago
  @polemic @shantanubala `stringify` and `parse` are the names specified by the ECMAScript language spec: http://es5.github.com/#x15.12.3 http://es5.github.com/#x15.12.3
  - polemic 15y ago
    Ah, ok. Thanks!
firefoxman1 15y ago
On issue 28, it says that when you do JSON.stringify(Object('hi')) The issue reporter says it should return '"hi"' but returns '{"0":"h","1":"i"}' In my JS console, if I do Object('hi') It returns { '0': 'h', '1': 'i' } So to me, it looks like JSON2 correctly serializes the result of Object('hi'). Am I missing something? https://github.com/douglascrockford/JSON-js/issues/28 https://github.com/douglascrockford/JSON-js/issues/28
- jdd 15y ago
  Make sure you're not on a page with external scripts that could be mucking it up. If you're recent modern browser `JSON.stringify(Object('hi'))` should produce '"hi"'. See http://cl.ly/2J3B0e1z1o3e0T3x2b0l http://cl.ly/2J3B0e1z1o3e0T3x2b0l.
  - firefoxman1 15y ago
    Right, JSON.stringify(Object('hi')) does that, but just plain Object('hi') without wrapping in stringify returns { '0': 'h', '1': 'i' } Is it part of the JSON spec that you first call .toString() on array-like objects?
    - jdd 15y ago
      `Object('hi')` produces the equivalent of `new String('hi')`. The stringify behavior is spec'ed here http://es5.github.com/#x15.12.3 http://es5.github.com/#x15.12.3 [Step 4b of the abstract operation Str(key, holder) algorithm]. See http://cl.ly/2E1l2X3X3U1B2N1d3G1k http://cl.ly/2E1l2X3X3U1B2N1d3G1k.
      - firefoxman1 15y ago
        Ahh that makes sense. I appreciate your research finding that part in the spec.
Gigablah 15y ago
Your git clone link seems to be outdated, it should be https://github.com/bestiejs/json3.git https://github.com/bestiejs/json3.git .
- kitcambridge 15y ago
  Fixed. Thank you!

41 points by kitcambridge 15y ago

Thanks for the heads up. I’ve always thought JSON2’s approach of adding all kinds of stuff to built-in objects was a dumb idea for such an important piece of infrastructure code. I’ve been tempted on occasion to write my own JSON codec. I’m glad they tested to make sure it works on every browser of the last 6-7 years: it means JSON3 can pretty much be dropped in and forgotten about for any project. Unrelated: their readme reveals a bug in github’s markdown implementation. The bold is not properly applied in the following example: - **`String.prototype` Methods**: `indexOf`, `charAt`, `slice`.

kitcambridge 15y ago
Fixed. Thanks for the heads-up!

spicyj 15y ago

I'd be slightly worried that overriding the native functions could lead to problems in certain situations that rely on the (wrong) existing behavior.

udp 15y ago
I don't think it's intended as a replacement for the native functions, rather an implementation to use where they're missing (which, AFAIK, is rare nowadays).
- spicyj 15y ago
  If you read the description on the page, it says that they fix certain broken aspects of some native implementations.
  - jdd 15y ago
    @spicyj I agree that recklessly paving natives is no good and can cause problems, but JSON3 is trying rather hard to not pave them (note that it doesn't even extend Date.prototype), and only paves parse/stringify when fixing broken implementations that are not cross-browser consistent or spec-compliant. With the fix in place it means the API will produce consistent output cross-browser which is a good thing.
  - kitcambridge 15y ago
    That's correct. Currently, Firefox is the only browser that implements the JSON routines exactly as described in the spec (parsing since version 5.0, and serializing since 6.0)...others deviate in one or more ways. It's not so much of a concern if you're targeting multiple browsers, as Firefox will correctly throw a `SyntaxError` when given malformed input, but it can certainly become problematic if you're relying on non-standard extensions in only one or two browsers.

deleted 15y ago

[deleted]

arturadib 15y ago

Speaking of new JSON versions, is it impossible to create a backwards-compatible JSON spec that supports comments? I've been waiting for this for ages.

jsdalton 15y ago
Please, yes. Two use cases where I constantly bemoan the lack of comment support in JSON are configuration files and test fixtures.
kitcambridge 15y ago
I, too, would love to see comments officially supported in the next iteration of the JSON standard...IIRC, Crockford removed them to make JSON a valid YAML subset. For what it's worth, I've created a fork of Kyle Simpson's `JSON.minify` project that uses a variation of the character-based parsing process in JSON 3: https://github.com/kitcambridge/JSON.minify/blob/master/minify-sans-regexp.js https://github.com/kitcambridge/JSON.minify/blob/master/mini... It's somewhat cumbersome to use, though, as it needs to be called on a string before feeding it to `parse` (e.g., `JSON.parse(JSON.minify("/* Hello */ 123"))`).
kodablah 15y ago
Optional quotes and optional EOL commas would be nice too
- akavlie 15y ago
  While more human friendly, that would inhibit serialization.
wvenable 15y ago
Comments were removed for several reasons; one being that it adds the ability to add non-JSON data to the stream. In order to keep the spec simple and more interoperable, comments are gone. Don't expect them to return.

steele 15y ago

unicode support? damn you u+2028

prodigal_erik 15y ago

If anyone else was confused, a "polyfill" is a pure javascript implementation of behavior the platform doesn't natively provide, and calling it "JSON 3" is not trying to claim that the JSON grammar has been revised (that's pretty much impossible); it's just the unfortunately generic name they chose for this implementation.

benatkin 15y ago
I understood the JSON3 name right away. Douglas Crockford's best-known implementation is called JSON2; this aims to be a successor to it. I agree that it shouldn't be called a polyfill.
jdd 15y ago
@prodigal_erik @benatkin It is a JS polyfill/shim/fallback for older browsers like IE 6 and 7 but also fixes/fills in gaps in support/consistency with modern browsers that have buggy implementations. The use of the word "modern" in the description is to suggest it is more up-to-date than Crockford's aging/stale json2.js.

polemic 15y ago

This is bike-shed, but `stringify`? What's wrong with `serialize` or `toJSON` or `toString'?

shantanubala 15y ago
This is mainly for consistency with the previous JSON libraries developed by Douglas Crockford. In JavaScript, it's easy enough to "create your own API" by just aliasing JSON.stringify to JSON.serialize or even a local "serialize" function that it isn't too much of an issue. As much as I agree that the naming convention isn't great, it's better to have consistency -- especially in a language as dynamic as JavaScript.
jdd 15y ago
@polemic @shantanubala `stringify` and `parse` are the names specified by the ECMAScript language spec: http://es5.github.com/#x15.12.3 http://es5.github.com/#x15.12.3
- polemic 15y ago
  Ah, ok. Thanks!

firefoxman1 15y ago

On issue 28, it says that when you do JSON.stringify(Object('hi')) The issue reporter says it should return '"hi"' but returns '{"0":"h","1":"i"}' In my JS console, if I do Object('hi') It returns { '0': 'h', '1': 'i' } So to me, it looks like JSON2 correctly serializes the result of Object('hi'). Am I missing something? https://github.com/douglascrockford/JSON-js/issues/28 https://github.com/douglascrockford/JSON-js/issues/28

jdd 15y ago
Make sure you're not on a page with external scripts that could be mucking it up. If you're recent modern browser `JSON.stringify(Object('hi'))` should produce '"hi"'. See http://cl.ly/2J3B0e1z1o3e0T3x2b0l http://cl.ly/2J3B0e1z1o3e0T3x2b0l.
- firefoxman1 15y ago
  Right, JSON.stringify(Object('hi')) does that, but just plain Object('hi') without wrapping in stringify returns { '0': 'h', '1': 'i' } Is it part of the JSON spec that you first call .toString() on array-like objects?
  - jdd 15y ago
    `Object('hi')` produces the equivalent of `new String('hi')`. The stringify behavior is spec'ed here http://es5.github.com/#x15.12.3 http://es5.github.com/#x15.12.3 [Step 4b of the abstract operation Str(key, holder) algorithm]. See http://cl.ly/2E1l2X3X3U1B2N1d3G1k http://cl.ly/2E1l2X3X3U1B2N1d3G1k.
    - firefoxman1 15y ago
      Ahh that makes sense. I appreciate your research finding that part in the spec.

Gigablah 15y ago

Your git clone link seems to be outdated, it should be https://github.com/bestiejs/json3.git https://github.com/bestiejs/json3.git .

kitcambridge 15y ago
Fixed. Thank you!