A nicer CSON.stringify

lib/cson-safe.js

@@ -34,6 +34,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 void function () {
   var CS, CSON, csr, find, isLiteral, LiteralTypes, nodeTransforms, nodeTypeString, parse, stringify, syntaxErrorMessage, transformKey, transformNode;
   csr = require('coffee-script-redux');
+  stringify = require('./stringify');
   CS = csr.Nodes;
   find = function (arr, testFn) {
     var element;
@@ -206,9 +207,6 @@ void function () {
       throw new SyntaxError(syntaxErrorMessage(csNode, 'Unexpected ' + nodeTypeString(csNode)));
     return transform[1](csNode);
   };
-  stringify = function (obj, visitor, indent) {
-    return JSON.stringify(obj, visitor, indent);
-  };
   parse = function (source, reviver) {
     var coffeeAst;
     if (reviver)

lib/stringify.js

@@ -0,0 +1,125 @@
+/*
+Copyright (c) 2014, Groupon, Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+
+Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+Neither the name of GROUPON nor the names of its contributors may be
+used to endorse or promote products derived from this software without
+specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+// Generated by CoffeeScript 2.0.0-beta8
+module.exports = function (obj, visitor, indent) {
+  var indentLine, indentLines, jsIdentifierRE, n, newlineWrap, serialize, tripleQuotesRE;
+  if (typeof obj === 'undefined' || typeof obj === 'function')
+    return;
+  indent = function () {
+    switch (typeof indent) {
+    case 'string':
+      return indent.slice(0, 10);
+    case 'number':
+      n = Math.min(indent, 10);
+      if (!in$(n, [
+          1,
+          2,
+          3,
+          4,
+          5,
+          6,
+          7,
+          8,
+          9,
+          10
+        ]))
+        n = 0;
+      return Array(n + 1).join(' ');
+    default:
+      return 0;
+    }
+  }.call(this);
+  if (!indent)
+    return JSON.stringify(obj, visitor, indent);
+  indentLine = function (line) {
+    return indent + line;
+  };
+  indentLines = function (str) {
+    return str && str.split('\n').map(indentLine).join('\n');
+  };
+  newlineWrap = function (str) {
+    return str && '\n' + str + '\n';
+  };
+  jsIdentifierRE = /^[a-z_$][a-z0-9_$]*$/i;
+  tripleQuotesRE = new RegExp("'''", 'g');
+  obj = JSON.parse(JSON.stringify(obj, visitor));
+  return (serialize = function (obj) {
+    var array, key, keypairs, object, string, val;
+    switch (typeof obj) {
+    case 'boolean':
+      return obj + '';
+    case 'number':
+      if (isFinite(obj)) {
+        return obj + '';
+      } else {
+        return 'null';
+      }
+    case 'string':
+      if (obj.indexOf('\n') === -1) {
+        return JSON.stringify(obj);
+      } else {
+        string = obj.replace(tripleQuotesRE, "\\'''");
+        string = newlineWrap(indentLines(string));
+        return "'''" + string + "'''";
+      }
+    case 'object':
+      if (obj === null) {
+        return 'null';
+      } else if (Array.isArray(obj)) {
+        array = obj.map(serialize).join('\n');
+        array = newlineWrap(indentLines(array));
+        return '[' + array + ']';
+      } else {
+        keypairs = function (accum$) {
+          for (key in obj) {
+            val = obj[key];
+            if (!key.match(jsIdentifierRE))
+              key = JSON.stringify(key);
+            val = serialize(val);
+            accum$.push('' + key + ': ' + val);
+          }
+          return accum$;
+        }.call(this, []);
+        object = keypairs.join('\n');
+        object = newlineWrap(indentLines(object));
+        return '{' + object + '}';
+      }
+    }
+  })(obj);
+};
+function in$(member, list) {
+  for (var i = 0, length = list.length; i < length; ++i)
+    if (i in list && list[i] === member)
+      return true;
+  return false;
+}

src/cson-safe.coffee

@@ -31,6 +31,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ###
 
 csr = require 'coffee-script-redux'
+stringify = require './stringify'
 CS = csr.Nodes
 
 find = (arr, testFn) ->
@@ -128,12 +129,6 @@ transformNode = (csNode) ->
 
   transform[1] csNode
 
-stringify = (obj, visitor, indent) ->
-  # Since CSON is a superset of JSON, we can just use the JSON serialization
-  # There are multiple ways to express the same thing in CSON, so trying to
-  # make `CSON.stringify(CSON.parse(str)) == str` work is doomed to fail
-  JSON.stringify obj, visitor, indent
-
 parse = (source, reviver) ->
   if reviver
     throw new Error "The reviver parameter is not implemented yet"

src/stringify.coffee

@@ -0,0 +1,69 @@
+# There are multiple ways to express the same thing in CSON, so trying to
+# make `CSON.stringify(CSON.parse(str)) == str` work is doomed to fail
+# but we can at least make output look a lot nicer than JSON.stringify's.
+module.exports = (obj, visitor, indent) ->
+  return undefined if typeof obj in ['undefined', 'function']
+
+  # pick an indent style much as JSON.stringify does, but limited to cson legals
+  indent = switch typeof indent
+    when 'string' then indent.slice 0, 10
+
+    when 'number'
+      n = Math.min indent, 10
+      n = 0 unless n in [1..10] # do not bail on NaN and similar
+      Array(n + 1).join ' '
+
+    else 0
+
+  return JSON.stringify obj, visitor, indent unless indent
+
+  indentLine = (line) -> indent + line
+
+  indentLines = (str) ->
+    str and str.split('\n').map(indentLine).join('\n')
+
+  newlineWrap = (str) ->
+    str and "\n#{ str }\n"
+
+  jsIdentifierRE = /^[a-z_$][a-z0-9_$]*$/i
+  tripleQuotesRE = new RegExp "'''", 'g' # some syntax hilighters hate on /'''/g
+
+  # have the native JSON serializer do visitor transforms & normalization for us
+  obj = JSON.parse JSON.stringify obj, visitor
+
+  do serialize = (obj) ->
+    switch typeof obj
+      when 'boolean' then obj + ''
+
+      when 'number'
+        if isFinite obj
+          obj + ''
+        else # NaN, Infinity and -Infinity
+          'null'
+
+      when 'string'
+        if obj.indexOf('\n') is -1
+          JSON.stringify obj
+        else
+          string = obj.replace tripleQuotesRE, "\\'''"
+          string = newlineWrap indentLines string
+          "'''#{ string }'''"
+
+      when 'object'
+        if obj is null
+          'null'
+
+        else if Array.isArray obj
+          array = obj.map(serialize).join '\n'
+          array = newlineWrap indentLines array
+          "[#{ array }]"
+
+        else
+          keypairs = for key, val of obj
+            key = JSON.stringify key unless key.match jsIdentifierRE
+            val = serialize val
+            "#{ key }: #{ val }"
+
+          object = keypairs.join '\n'
+          object = newlineWrap indentLines object
+          "{#{ object }}"

test/stringify.coffee

@@ -1,8 +1,122 @@
 
-assert = require 'assertive'
+{ equal } = require 'assertive'
 
 CSON = require '../'
+cson = (obj, visitor, space = 2) -> CSON.stringify obj, visitor, space
 
 describe 'CSON.stringify', ->
-  it 'works just like JSON.stringify', ->
-    assert.equal '{"a":"b"}', CSON.stringify(a: 'b')
+  it 'handles null', ->
+    equal 'null', cson null
+
+  it 'handles boolean values', ->
+    equal 'true',  cson true
+    equal 'false', cson false
+
+  it 'handles the empty object', ->
+    equal '{}', cson {}
+
+  it 'handles the empty array', ->
+    equal '[]', cson []
+
+  it 'handles numbers', ->
+    equal '0.42',    cson 0.42
+    equal '42',      cson 42
+    equal '1.2e+90', cson 1.2e+90
+
+  it 'handles single-line strings', ->
+    equal '"hello!"', cson 'hello!'
+
+  it 'handles multi-line strings', ->
+    equal """
+      '''
+        I am your average multi-line string,
+        and I have a sneaky \\''' in here, too
+      '''
+    """, cson """
+      I am your average multi-line string,
+      and I have a sneaky ''' in here, too
+    """
+
+  it 'handles arrays', ->
+    equal '''
+      [
+        [
+          1
+        ]
+        null
+        []
+        {
+          a: "str"
+        }
+      ]
+    ''', cson [ [1], null, [], a: 'str' ]
+
+  it 'handles objects', ->
+    equal '''
+      {
+        "": "empty"
+        "non\\nidentifier": true
+        default: false
+        nested: {
+          string: "too"
+        }
+        array: [
+          {}
+          []
+        ]
+      }
+    ''', cson {
+      '': 'empty'
+      "non\nidentifier": true
+      default: false
+      nested: {
+        string: 'too'
+      }
+      array: [
+        {}
+        []
+      ]
+    }
+
+  it 'handles NaN and +/-Infinity like JSON.stringify does', ->
+    equal 'null', cson NaN
+    equal 'null', cson +Infinity
+    equal 'null', cson -Infinity
+
+  it 'handles undefined like JSON.stringify does', ->
+    equal undefined, cson undefined
+
+  it 'handles functions like JSON.stringify does', ->
+    equal undefined, cson ->
+
+  it 'works just like JSON.stringify when asking for no indentation', ->
+    equal '{"zeroed":0}', cson zeroed: 0, null, 0
+    equal '{"empty":""}', cson empty: '', null, ''
+
+  it 'accepts no more than ten indentation steps, just like JSON.stringify', ->
+    equal '''
+      {
+                "don't": "be silly, will'ya?"
+      }
+    ''', cson {"don't": "be silly, will'ya?"}, null, Infinity
+
+  it 'lets people that really want to indent with tabs', ->
+    equal '''
+      {
+      \t\t"super-tabby": true
+      }
+    ''', cson {'super-tabby': yes}, null, '\t\t'
+
+  it 'is bug compatible with JSON.stringify for non-whitespace indention', ->
+    equal '''
+      {
+      ecma-262strange: true
+      }
+    ''', cson {strange: yes}, null, 'ecma-262'
+
+  it 'handles visitor functions', ->
+    equal '''
+      {
+        keep: 1
+      }
+    ''', cson {filter: 'me', keep: 1}, (k, v) -> v unless typeof v is 'string'