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Re: [json] json.js breaks for-in loops

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  • Scott Chapman
    It s easy to modify json.js so it doesn t extend Object.prototype. That was a bad design in my opinion. The version I use is attached. Scott ... [Non-text
    Message 1 of 10 , Oct 14, 2006
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      It's easy to modify json.js so it doesn't extend Object.prototype. That was a
      bad design in my opinion.

      The version I use is attached.

      Scott

      Peter Michaux wrote:
      > Hi,
      >
      > By extending the Object.prototype with the new property toJSONString I
      > can no longer use for-in loops in my JavaScript.
      >
      > Has someone released a version of JSON that doesn't do this?
      >
      > Is it just as simple as changing these
      >
      > Object.prototype.toJSONString = function () {
      > Array.prototype.toJSONString = function () {
      > String.prototype.parseJSON = function () {
      >
      > to something like
      >
      > JSON.objectToJSONString = function () {
      > JSON.arrayToJSONString = function () {
      > JSON.parseJSON = function () {
      >
      > or are their other catches that I have missed?
      >
      > Thank you,
      > Peter



      [Non-text portions of this message have been removed]
    • Martin Cooper
      ... It s not just exceptionally bad design, it s chronically inconsiderate programming. Nobody could use that code inside portlets, because they d risk
      Message 2 of 10 , Oct 14, 2006
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        On 10/14/06, Scott Chapman <scott_list@...> wrote:
        >
        > It's easy to modify json.js so it doesn't extend Object.prototype. That
        > was a
        > bad design in my opinion.


        It's not just exceptionally bad design, it's chronically inconsiderate
        programming. Nobody could use that code inside portlets, because they'd risk
        breaking any and all other JavaScript on the same portal page over which
        they have no control. Even outside a portal environment, it's going to break
        other libraries that developers might already be using, not to mention their
        own code.

        --
        Martin Cooper


        The version I use is attached.
        >
        > Scott
        >
        > Peter Michaux wrote:
        > > Hi,
        > >
        > > By extending the Object.prototype with the new property toJSONString I
        > > can no longer use for-in loops in my JavaScript.
        > >
        > > Has someone released a version of JSON that doesn't do this?
        > >
        > > Is it just as simple as changing these
        > >
        > > Object.prototype.toJSONString = function () {
        > > Array.prototype.toJSONString = function () {
        > > String.prototype.parseJSON = function () {
        > >
        > > to something like
        > >
        > > JSON.objectToJSONString = function () {
        > > JSON.arrayToJSONString = function () {
        > > JSON.parseJSON = function () {
        > >
        > > or are their other catches that I have missed?
        > >
        > > Thank you,
        > > Peter
        >
        >
        >
        > [Non-text portions of this message have been removed]
        >
        >
        >
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        >


        [Non-text portions of this message have been removed]
      • Stephen M. McKamey
        ... toJSONString I ... make ... A little late to the conversation but... another alternative could be to use the typeof operator (assuming one was iterating
        Message 3 of 10 , Nov 13, 2006
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          --- In json@yahoogroups.com, Tom Metro <tmetro+json@...> wrote:
          >
          > Peter Michaux wrote:
          > > By extending the Object.prototype with the new property
          toJSONString I
          > > can no longer use for-in loops in my JavaScript.
          >
          > As another poster mentioned, using hasOwnProperty(), is the way to
          make
          > the intended behavior work. My understanding is that hasOwnProperty()
          > isn't widely supported yet.

          A little late to the conversation but... another alternative could be
          to use the typeof operator (assuming one was iterating over data):

          for(k in obj)
          if("function"!=typeof obj[k])
          foo(k);

          Thanks,
          smm
        • Martin Cooper
          ... Sure - if the for loop is in your own code, and not some other package that you re just trying to make use of. This issue really needs to be fixed in the
          Message 4 of 10 , Nov 13, 2006
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            On 11/13/06, Stephen M. McKamey <jsonml@...> wrote:
            >
            > --- In json@yahoogroups.com, Tom Metro <tmetro+json@...> wrote:
            > >
            > > Peter Michaux wrote:
            > > > By extending the Object.prototype with the new property
            > toJSONString I
            > > > can no longer use for-in loops in my JavaScript.
            > >
            > > As another poster mentioned, using hasOwnProperty(), is the way to
            > make
            > > the intended behavior work. My understanding is that hasOwnProperty()
            > > isn't widely supported yet.
            >
            > A little late to the conversation but... another alternative could be
            > to use the typeof operator (assuming one was iterating over data):
            >
            > for(k in obj)
            > if("function"!=typeof obj[k])
            > foo(k);


            Sure - if the for loop is in your own code, and not some other package that
            you're just trying to make use of.

            This issue really needs to be fixed in the JSON code, since there's no way
            you can rely on it being fixed in all the other code out there that you
            might want to use.

            --
            Martin Cooper


            Thanks,
            > smm
            >
            >
            >
            >
            >
            > Yahoo! Groups Links
            >
            >
            >
            >
            >


            [Non-text portions of this message have been removed]
          • Stephen M. McKamey
            // This should do what you are asking for while staying // current with Crockford s latest code: // after json.js has loaded... // define a namespace to
            Message 5 of 10 , Nov 13, 2006
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              // This should do what you are asking for while staying
              // current with Crockford's latest code:

              // after json.js has loaded...
              // define a namespace to minimize footprint
              var JSON = {};

              // add all of the methods
              JSON.arrayToJSONString = Array.prototype.toJSONString;
              JSON.booleanToJSONString = Boolean.prototype.toJSONString;
              JSON.dateToJSONString = Date.prototype.toJSONString;
              JSON.numberToJSONString = Number.prototype.toJSONString;
              JSON.objectToJSONString = Object.prototype.toJSONString;
              JSON.stringToJSONString = String.prototype.toJSONString;
              JSON.parseJSON = String.prototype.parseJSON;

              // remove all the methods from intrinsic objects
              delete(Array.prototype.toJSONString);
              delete(Boolean.prototype.toJSONString);
              delete(Date.prototype.toJSONString);
              delete(Number.prototype.toJSONString);
              delete(Object.prototype.toJSONString);
              delete(String.prototype.toJSONString);
              delete(String.prototype.parseJSON);

              --- In json@yahoogroups.com, "Martin Cooper" <mfncooper@...> wrote:
              > Sure - if the for loop is in your own code, and not some other
              package that
              > you're just trying to make use of.
              >
              > This issue really needs to be fixed in the JSON code, since there's
              no way
              > you can rely on it being fixed in all the other code out there that
              you
              > might want to use.
            • Martin Cooper
              ... Right. But I don t understand the resistance (or, actually, just lack of any feedback at all) to having the kind of solution I described before (in another
              Message 6 of 10 , Nov 13, 2006
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                On 11/13/06, Stephen M. McKamey <jsonml@...> wrote:
                >
                > // This should do what you are asking for while staying
                > // current with Crockford's latest code:


                Right. But I don't understand the resistance (or, actually, just lack of any
                feedback at all) to having the kind of solution I described before (in
                another thread) incorporated into the original source code, so that we don't
                have to be going and deleting things like that. Here's what I suggested
                before, which is largely the same as yours, except that mine avoids creation
                where yours utilises deletion and is necessarily separate (and hence a
                little less easily maintained) from the original:

                http://tech.groups.yahoo.com/group/json/message/557

                --
                Martin Cooper


                // after json.js has loaded...
                > // define a namespace to minimize footprint
                > var JSON = {};
                >
                > // add all of the methods
                > JSON.arrayToJSONString = Array.prototype.toJSONString;
                > JSON.booleanToJSONString = Boolean.prototype.toJSONString;
                > JSON.dateToJSONString = Date.prototype.toJSONString;
                > JSON.numberToJSONString = Number.prototype.toJSONString;
                > JSON.objectToJSONString = Object.prototype.toJSONString;
                > JSON.stringToJSONString = String.prototype.toJSONString;
                > JSON.parseJSON = String.prototype.parseJSON;
                >
                > // remove all the methods from intrinsic objects
                > delete(Array.prototype.toJSONString);
                > delete(Boolean.prototype.toJSONString);
                > delete(Date.prototype.toJSONString);
                > delete(Number.prototype.toJSONString);
                > delete(Object.prototype.toJSONString);
                > delete(String.prototype.toJSONString);
                > delete(String.prototype.parseJSON);
                >
                > --- In json@yahoogroups.com, "Martin Cooper" <mfncooper@...> wrote:
                > > Sure - if the for loop is in your own code, and not some other
                > package that
                > > you're just trying to make use of.
                > >
                > > This issue really needs to be fixed in the JSON code, since there's
                > no way
                > > you can rely on it being fixed in all the other code out there that
                > you
                > > might want to use.
                >
                >
                >
                >
                >
                >
                > Yahoo! Groups Links
                >
                >
                >
                >
                >


                [Non-text portions of this message have been removed]
              • Douglas Crockford
                JavaScript is an imperfect language. The weird interaction between augmentation of prototypes with the for..in statement is evidence of this. This defect in
                Message 7 of 10 , Nov 14, 2006
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                  JavaScript is an imperfect language. The weird interaction between
                  augmentation of prototypes with the for..in statement is evidence of
                  this. This defect in the language requires that for..in blocks
                  explicitly filter out unwanted stuff that is dredged up from the
                  prototype chain. See http://yuiblog.com/blog/2006/09/26/for-in-intrigue/

                  json.js provides the same API that will be built into ECMAScript
                  Fourth Edition. That means that if your program works with json.js,
                  then it will work even better when the language is revised.

                  Some people do not have the luxury of being forward looking. They have
                  to work with bad code that does not filter for..in, or they claim the
                  right to write bad code themselves. Those people should not be using
                  json.js. Fortunately, JSON encoding and decoding is so easy, there
                  isn't much effort required to make an implementation that works with
                  bad code.

                  JSON is a standard data representation. The json.js implementation is
                  not the standard. It is a reference implementation. You are free to
                  use it in any way that you want, or to not use it.
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